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HOOKWOKM  DISEASE 


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HOOKWOKM    DISEASE 


ETIOLOfxY.  PATHOLOGY.  DIAGNOSIS.  PEOCtXOSIS, 

PEOPHYLAXIS.  AM)  TPtEAT3IEXT 


GfEORGE  DOCK,  A.M..  M.  D.. 

PROFES.SOK    OF    THE    THEORY   A>rX>    PKACTICE    OF    MEDICIXE,    MEDICAL 
DEPARTMENT    TULAXE   r^N'IVEKSITY    OF    LOUISIANA,    NEW    ORLE4.SS, 

AX  J; 

CHAELES  r.  BASS,  M.  D., 

IX.STRIXTOK    OF    CLINICAL    MICROSCOPY   AND    CLINICAL   MEDICINE,    MEDICAL 
DEPARTMENT   TCLANE   rNTVERSITY   OF   LOUISIANA,   NEW   ORLEANS. 


ILLUSTRATED  WITH  FORTY-NINE  SPECIAL 
EXGRAVLVGS  AND  COLORED  PLATE 


ST.  LOUIS 
C.  V.  MOSBY  COMPANY 

1910 


Copyright,  1910,  by  C.  V.  Mosby  Company' 


TO 

CHARLES  WARDELL  STILES,  Ph.  D.,  D.  Sc, 

Chief  of  the  Divisiot^  of  Zoology  in  the  Hygienic  Laboratory,  United 

States  Public  Health  and  Marine  Service, 
Whose  brilliant  conceptions   and  untiring  labors  hwe  enlarged  our 

knowledge   of    HOOKWORil  DISEASE,   AND  THEREBY  OPENED  UP   ONE  OF 
THE    MOST    IMPORTANT    FIELDS    OF    PREVENTIVE    MEDICINE, 

THIS   VOLUME   IS    DEDICATED    BY 

THE  AUTHORS. 


PREFACE. 


Few  diseases  surpass  the  subject  .of  this  work  in  the 
strangeness  of  its  history,  the  importance  of  its  ravages,  or 
the  theoretic  ease  of  its  extinction. 

It  probably  existed  from  remote  antiquity  among  trop- 
ical peoples,  and,  although  attempts  have  been  made  to 
trace  it  back  to  a  very  early  period,  these  efforts  fail  for 
lack  of  the  careful  clinical  methods  of  diagnosis  that  are 
necessary  for  the  recognition  of  such  diseases.  For  almost 
fifty  years  after  the  disease  was  made  known  in  Italy,  and 
after  it  had  been  the  subject  of  many  important  investiga- 
tions in  diagnosis,  biology,  and  treatment,  it  remained  for 
us  in  America  chiefly  an  interesting,  but  remote,  fact,  de- 
void of  practical  relations.  Its  absence  was  accepted  as 
evidence  of  the  greater  personal  cleanliness  and  superior 
mode  of  life  of  our  citizens,  and  at  most  it  was  feared  that 
among  recent  immigrants  cases  might  be  imported  and  even 
spread  in  less  favorable  localities.  No  more  striking  ex- 
ample of  the  transitory  state  of  medical  knowledge  can  be 
advanced  than  the  proof  brought  within  the  last  few  years, 
not  only  that  hookworms  exist  as  human  parasites  in  a 
large  part  of  the  country,  but  that  they  may  with  reason  be 
looked  upon  as  among  the  most  important  causes  of  diseases 
of  the  South  in  extent,  in  destruction  of  life,  and  in  leading 
to  physical  and  mental  degeneration.  The  fact  that  the 
parasites  in  the  United  States  belong  to  a  new  species  is  a 
most  important  one  and  very  suggestive  in  its  bearing  on 
medical  zoology. 

9 


10  PEEFACE. 

In  many  parts  of  Europe  hookworm  disease  is  one  of  the 
most  important  economic  problems.  Immense  labor  and 
expense  have  been  devoted  to  the  measures  for  its  repres- 
sion in  Belgium  and  Germany  especially,  where  it  seriously 
affects  the  mining  industry. 

The  study  of  hookworm  disease  in  America  has  shown 
the  heav}"  load  that  endemic  disease  lays  upon  a  country. 
Largely  due  to  it,  a  region  that  should  be  most  fertile  lies 
relatively  uncultivated;  a  population  derived  from  the  best 
colonizing  blood  ekes  out  a  miserable  existence,  and  is 
doomed  to  extinction  unless  it  is  soon  relieved  of  its  infec- 
tion. Thanks  to  the  painstaking  labors  of  zoologists  and 
physicians,  much  has  been  learned  of  the  disease  and  its 
parasite.  Physicians  and  hygienists  have  realized  that  the 
evil,  preventable  as  it  is,  must  stop,  and  medical  men,  ad- 
ministrative officers,  and  private  philanthropists  are  now 
working  actively  to  that  end. 

In  the  widespread  effort  at  extermination  many  forces 
must  co-operate.  Physicians  will  be  called  upon  to  treat 
the  disease  in  its  various  forms,  as  well  as  to  assist  in  its 
prevention.  For  them  j^rimarily  this  book  has  been  writ- 
ten, for  the  authors  have  for  a  long  time  been  interested  in 
the  medical  features  of  the  disease.  Hygienists,  employers 
of  labor,  and  others  interested  in  sanitation  may  also  find 
information  of  practical  value.  How  well  we  have  suc- 
ceeded we  leave  to  our  readers.  We  take  pleasure  in 
thanking  many  well-known  authorities  for  the  use  of 
material  and  illustrations,  especially  Dr.  C.  W.  Stiles,  Allen 
J.  Smith,  Claude  A.  Smith,  and  H.  F.  Harris.  Many  others 
whose  works  we  have  drawn  upon  freely,  and  who  have 
accomplished  important  work  on  the  subject,  are  mentioned 
in  the  following  pages. 

"We  have  avoided  bibliographic  references,  except  in  rare 
instances,  believing  that  those  who  wish  to  consult  original 


PEEFACE.  11 

sources  will  have  to  use  the  "Index  Medicus"  in  any  event. 
We  have  also  repeated  certain  statements  in  order  to  make 
easier  the  use  of  the  book  for  reference  by  those  who  wish 
to  gather  practical  lessons  from  it. 


CONTENTS. 


CHAPTER    I. 

PAflK 

Definition — Synonyms — Historical — IVCythical  period — Early  references 
in  seventeenth,  eighteenth,  and  early  nineteenth  centuries — Du- 
bini  and  the  recognition  of  ankylostoma  in  the  human  body — 
Bilharz,  Griesinger,  and  others,  and  the  recognition  of  pathologic 
relations — St.  Gothard  tunnel  anemia  and  the  lesson  it  gave — 
Work  of  Perroncito,  Parona,  and  others  in  Italy,  Switzerland,  and 
Germany — Leichten stern  and  the  anemia  of  brick  workers  and 
miners— Early  references  to  hookworm  disease  in  America  under 
the  names  of  dirt  eating,  malarial  cachexia,  etc. — Later  history, 
with  the  discoveries  of  A.  J.  Smith,  Harris,  Stiles,  Claude  A. 
Smith,  and  others — Discovery  of  the  skin  infection  by  Looss  and 
its   confirmation   by   others 17 

CHAPTER  II. 

United  States — Geographic  distribution — Intensity — Economic  impor- 
tance— Climate — Soil — Occupation — ^Barefooted  Children     ...       33 

CHAPTER   III. 

Zoologic  features — Clasaification  of  hookworms — Nearly  related,  simi- 
lar, and  allied  worms — ^Historic  data  regarding  nomenclature, 
genera,  and  species — Ankylostoma  duodenale — Anatomy — Necator 
Americanus — Development — Reproduction — Existence  outside  the 
human    body — Effects    of    chemical    disinfectants 46 

CHAPTER  IV. 

Modes  of  infection — Conditions  that  favor  development  of  larvae — In- 
fection by  drinking  water  and  by  food — Skin — Ground  itch  and 
its  relation  to  infection  by  hookworms — Disposition  of  feces  and 
its  part  in  hookworm  infection     ...  . 70 

CHAPTER   V. 

Pathologic  anatomy  and  pathology — Post-mortem  appearances — Blood 
— Skin — Intestines — Pathology — Anemia  and  its  causation,  as  by 
sucking  blood,  by  hemorrhage  following  bites,  by  hemolytic  and 
other  poisons — Loss  of  mucus — Lesions  of  the  intestine — Infec- 
tion of  the  bites — Blood  changes 94 

13 


li  CONTEXTS. 

CHAPTER   VI. 

PAGE 

Symptomatology — Varieties  of  types  and  different  degrees  of  in- 
tensity— Symptoms  and  signs  on  the  part  of  various  organs  and 
functions  in  detail — Blood — Joints — Skin — Ground  itch:  clinical 
features;  importance  in  early  diagnosis — Liver — Spleen — Respira- 
tory organs — Circulation — Digestive  organs — Dirt  eating — Genito- 
urinary organs — Eyes — Nervous  and  mental  symptoms     .      .      .     115 

CHAPTER   VII. 

Diagnosis — Direct  diagnosis  by  examination  of  feces  for  ova — Prac- 
tical examination  of  stools — Making  the  preparation  for  micro- 
scopic examination — Description  of  eggs — Number  of  worms  esti- 
mated from  eggs — Differential  diagnosis  of  eggs — Cultivation  of 
larvas  from  ova — Special  methods  for  greater  certainty  in  find- 
ing eggs:  Pepper's,  Bass' — Diagnosis  by  examining  stools  after 
treatment — Blotting  paper  test — Eosinophile  count  in  diagnosis     155 

CHAPTER  VIII. 

Prognosis — Prognosis  of  infection  in  various  types  of  disease  at 
various  ages — Mortality — Intercurrent  diseases  and  complications 
— Other   parasites 182 

CHAPTER    IX. 

Prophylaxis — Its  necessity  as  an  economic  and  sanitary  measure — 
Elements  of  prevention — Extermination  of  mature  woi'ms — Soil 
infection  and  its  prevention  in  theory  and  practice — Construc- 
tion and  care  of  privies — Disinfection  and  its  uncertainties — Dis- 
position of  feces — Preventive  measures  in  various  exposed  trades 
—Education 189 

CHAPTER  X. 

Treatment — ^Treatment  of  ground  itch — Treatment  before  ova  appear 
in  stool — Possibility  of  early  cure — Treatment  of  hookworms  in 
intestine — Preliminary  treatment  and  its  object — Thymol — 
Dose  of  thymol — Mode  of  administration — After-purgative  and 
its  object — Dangers  of  thymol  and  means  of  avoiding  them — 
Results  to  be  expected  from  thymol  treatment — Need  for  repe- 
tition of  treatment — Advantages  and  disadvantages  of  other 
methods  of  treatment — Beta-naphtol — Male  fern — Other  drugs — 
Treatment  of  symptoms  and  sequelae — Anemia — Improvement 
after  treatment 207 


ILLUSTEATIOXS. 


Intestinal    lesions    in    uncinariasis .      .     Frontispiece 

PAGE 

Fig.     1.     Female  uncinaria  duodenalis  and  uncinaria  Americana     .  51 

Fig.     2.     Male  hookworm 53 

Fig.  3.  Dorsal  view  of  anterior  end  of  the  old  world  hookworm  .  54 
Fig.     4.     Caudal   bursa   and    tail    of    male   uncinaria    duodenalis    and 

uncinaria  Americana 58 

Fig.     5.     Ankylostoma     duodenale     in     copulation 58 

Fig.     6.     Copulating     hookworms     from     dogs 58 

Fig.     7.     Male    and    female    necator    Americanus 59 

Fig.     8.     Dorsal  aspect  of   head  end   of  uncinaria  Americana     .      .  60 

Fig.  9.  Lateral  aspect  of  head  end  of  uncinaria  Americana  .  .  61 
Fig.  10.     Dorsal    view    of    head    end    of    uncinaria    duodenalis    and 

uncinaria  Americana 62 

Fig.  11.     Embryology  of  the  old  world  hookworm 62 

Fig.  12.     Two  larvse  of  the   old  world  hookworm 64 

Fig.  13.     Ova  of  uncinaria   duodenalis   and  uncinaria  Americana     .  65 

Fig.  14.  Experimental  hookworm  infection — Soil  containing  larvae  77 
Fig.  15.     Experimental   hookworm    infection — Swelling    of  wrist   and 

tendons   of  hand   and   vesicle   infection 77 

Fig.  16.  Experimental  hookworm  infection — Large  crust  forming  78 
Fig.  17.  Experimental  hookworm  infection — Confluent  vesicle  forma- 
tion        79 

Fig.  18.     Experimental  hookworm  infection — Uncinarise  removed  from 

intestines         80 

Fig.  19.     Section  of  skin  as  seen  under  the   microscope — Hookworm 

crawling    through    skin 81 

Fig.  20.     Hookworm    larvse    in    axillary    gland 82 

Fig.  21.     Hookworm    larvae    in    blood    in    heart 83 

Fig.  22.     Hookworm  larvae  in  lungs 84 

Fig.  23.     Hookworm  larvae  in  trachea 84 

Fig.  24.     Hookworm  larvae  in   larynx 85 

Fig.  25.     Privy  from  which  soil  pollution   is  being  spread     ...  87 

Fig.  26.     Privy  in  center   of  town 88 

E^g.  27.  Kind  of  privy  in  general  use  in  small  towns  ....  89 
Fig.  28.     Blood  cyst  below  mucosa  of  jejunum,  with  cross  section  of 

included    hookworm 99 

Fig.  29.     Hookworm    in    submucosa,    with    cross    section    of    body    of 

female         107 

15 


16  ILLUSTEATIONS. 

PAGE 

Fig.  30.  Photomicrograpli   of  uncinaria  Americana  sucking  mucosa  109 

Fig.  31.  Jejunum  in  a  fatal  case  of  uncinariasis 110 

Fig.  32.  Mother   and   three   children   with   hookworm    disease     .      .  116 

Fig.  33.  Family  of  seven  with  hookworm  disease 117 

Fig.  34.  Family    of   six   with    hookworm    disease 119 

Fig.  35.  Hookworm  case  of  average  severity  in  boy 120 

Fig.  36.  Same    subject    as    Fig.    35 — Slight    edema    of    face    and    ex- 

pre^ion  of  illness 121 

Fig.  37.  Seven-year  old  girl  with  hookworm  disease 122 

Fig.  38.  Hookworm  case  of  average  severity  in  girl 123 

Fig.  39.  Hookworm  case  of  severe  nature  in  boy  14  years  old     .      .  125 

Fig.  40.  Hookworm  case  of  severe  nature  in  boy  16  years  old     .      .  127 

Fig.  41.  Hookworm    subject    22    years    old 128 

Fig.  42.  Side  view   of  Fig.   41 129 

Fig.  43.  Rontgenogram  of  hand  of  hookworm  subject  shown  in  Fig.  41  130 

Fig.  44.  Rontgenogram  of  hand  of  normal  man  19  years  old     .      .  131 

Fig.  45.  Diluted  feces  on   slide   for   microscopic   examination     .      .  159 

Fig.  46.  Microscopic    appearance    of    feces 175 

Fig.  47.  Preparation  made  by  Bass'  method  from  feces     ....  176 

Fig.  48.  Sanitary    privy 196 

Fig.  49.  Sanitary    privy 197 


HOOKWOEM  DISEASE. 


CHAPTER  I. 
DEFINITION. 

Hookworm  disease  is  due  to  certain  species  of  hookworm 
(ankylostoma  duodenale,  sometimes  called  uncinaria  duo- 
denalis,  and  necator  Americanus)  which  live  as  parasites 
in  the  small  intestine.  It  occurs  especially  in  warm 
countries  and  in  certain  regions  in  temperate  latitudes 
where  the  climate  in  the  summer,  or  other  features — such 
as  warm  mines — offer  favorable  conditions;  chiefly  in 
persons  who  come  in  contact  with  damp  earth,  or  with 
water  containing  larvae  of  the  parasites.  It  is  character- 
ized by  the  discharge  of  the  ova  of  the  worms  with  the 
feces;  by  a  progressive  anemia,  weakness,  impaired  de- 
velopment in  young  subjects,  and  by  various  symptoms  on 
the  part  of  the  circulatory,  digestive,  and  nervous  systems, 
in  varying  degrees  and  combinations;  occasionally  fatal, 
it  is  capable  of  cure  by  removal  of  the  parasites  and  of  pre- 
vention by  hygienic  measures. 

The  term  ''hookworm  carrier"  is  applied  to  persons  in 
whom  hookworms  live  as  parasites,  but  who,  either  from 
small  number  of  worms,  from  race  immunity,  or  other 
causes,  do  not  develop  obvious  symptoms. 

The  importance  of  this  class  in  the  dissemination  of  the 
disease  is  very  great,  and  will  be  considered  in  the  follow- 
ing pages. 

17 


18  HOOKWORM  DISEASE. 

Synonyms. 

Ankylostomiasis ;  ancliylostomiasis ;  ankylostomasie 
(French). 

Anchilo^tomanemia  ( Italian ) . 

Ankylostomo-ana?mia  (Latin) . 

Ankylostomen-Krankheit  (German). 

Anquilostomiasis  (Spanish). 

Uncinariasis. 

Dochmiosis. 

Egyptian  or  tropical  chlorosis. 

Tunnelworker's  anemia;  tmmel  disease;  tnnnel  anemia. 

St.  Gothard  tunnel  disease. 

Brickmaker's  anemia. 

Mountain  cachexia;  mountain  anemia. 

Miner's  anemia;  miner's  cachexia;  anemie  d'Anzin. 

Anemie  des  pays  chauds;  anemia  of  Ceylon;  Porto  Eican 
anemia. 

Anemia  intertropicalis. 

Hypoaemia  intertropicalis. 

Malarial  anemia. 

Cachexia  Africana;  cachexia  Americana-;  cachexie 
aqueuse. 

Mai  d'estomac  (Pere  Labat.  174:2). 

Mai  de  cceur. 

Geophagia  (in  part). 

Allotriophagia  (in  part). 

Dirt  eating  (in  part). 

Xegro  consumption. 

Eihagan  (in  Eg}7)t  the  "yellows,"  Sandwitli). 

Opilacao  (Portuguese). 

Amerellao  (i.  e.,  "icterus"). 

Cangagao  (i.  e.,  "tired  feeling"). 

Pica  (in  part). 


DEFINITION.  19 

Malnutrition  (in  part). 
Tun-tun. 

The  synonyms  of  liookwoim  disease  indicate  the  wide 
range  of  symptoms,  as  well  as  the  extensive  geographic  dis- 
tribution, as  shown  by  the  diversity  of  languages. 

Historical. 

The  efforts  to  interpret  certain  statements  in  the  Ebers 
papyrus  (1550  B.  C.)  as  proof  of  the  knowledge  of  hook- 
worm disease  on  the  part  of  the  ancient  Egyptians  are 
purely  fanciful.  We  may  admit  that  the  disease  occurred 
in  Egypt  then  as  it  does  nov/,  and  we  may  also  accept  the 
ingenious  suggestion  of  Sambon  that  its  suspecteid  causa- 
tion was  related  to  the  veneration  of  the  dung  beetle,  the 
sacred  scarab.,  by  the  Egyj)tians.  But  even  if  the  symptom 
picture  was  clearly  recognized  then,  and  even  if  the  exist- 
ence of  the  parasites  was  known,  no  information  came  down 
to  assist  later  generations  in  the  recognition,  prevention, 
and  treatment  of  the  disease. 

The  history  of  hookworm  disease  is  identical,  as  we  now 
know,  with  that  of  cases  described  in  various  tropical  coun- 
tries during  three  centuries — viz.,  Piso  in  Brazil  (1648), 
Father  Labat  in  Guadeloupe  (1748),  Bryon  Edwards  in 
Jamaica  (1799),  under  various  names  as  given  in  the  list 
of  synonyms,  and  characterized  by  severe  abdominal  symp- 
toms, anemia,  dropsy,  and  weakness,  often  causing  death, 
chiefly  among  negro  slaves,  but  also  affecting  other  classes 
of  the  population.  At  the  time  the  true  nature  of  the  con- 
ditions described  was  not  understood  and  often  wholly  mis- 
interpreted, and  the  misinterpretation  continued  to  a  recent 
period.  This  is  particularly  true  as  regards  the  supposed 
relation  of  malaria  to  the  anemia,  and  hardly  less  so  to  the 
relation  of  dirt  eating,  warm  climates,  and  poverty. 


20  HOOKWORM  DISEASE. 

The  discovery  of  the  first  hookworms  in  1782  and  1789 
had  no  influence  on  clinical  study. 

Certain  diseases  of  miners  in  temperate  latitudes,  de- 
scribed by  older  writers,  can  also  be  explained  now  by  hook- 
worm infection.  Anemia  was  a  striking  symptom,  and  the 
"miner's  anemia"  sometimes  occurred  in  epidemics.  In 
1786  such  an  epidemic  broke  out  in  Schemnitz  in  Hungary, 
and  more  than  1,200  miners  were  affected.  There  were  sim- 
ilar epidemics  between  1802  and  1820  in  the  French  mines 
of  Anzin,  Fresnes,  Vieux-Conde,  Avize,  Escarpelle,  and 
Graissesac.  In  1875  the  Medical  Society  of  the  Loire  Basin 
investigated  the  epidemic  anemia.  Sporadic  cases  were 
observed  and  reported  in  Hungary  and  Bohemia.  Ham- 
merschmid  noted  that  the  disease  differed  from  ordinary 
anemia  or  chlorosis,  that  it  represented  a  disease  sui generis , 
and  that  the  explanation  by  the  mine  climate  or  vitiated  air 
was  not  satisfactory. 

In  1838  Dubini,  in  Milan,  found  what  he  thought  were 
previously  undescribed  worms  in  the  intestine  of  a  woman 
dead  of  pneumonia.  Four  years  later  he  found  some  more 
worms  of  the  same  kind  in  the  body  of  a  woman  dead  of 
hydrothorax,  and  on  a  third  occasion  in  the  body  of  a  man 
dead  of  jaundice.  In  these  three  cases  he  saw  only  female 
worms,  but  in  another  case  he  discovered  males,  and  later 
found  similar  worms  in  many  subjects,  either  free  in  the 
duodenum  and  jejunum,  or  hanging  on  to  the  mucosa  by 
their  mouths.  On  the  whole,  he  found  them  in  at  least  20 
percent  of  bodies  examined,  and  sometimes  in  company 
with  other  worms.  He  thought  the  worms  not  without 
effect  on  the  body,  though  not  causing  special  accidents; 
that  their  seat  was  especially  in  the  duodenum  or  upper 
half  of  the  jejunum;  that  an  unusual  amount  of  mucus  was 
essential  for  their  existence;  that  the  mucosa  in  the  parts 
affected  was  either  normal,  or  injected,  or  punctate,  red  or 


DEFINITION.  21 

black,  and  tliat  the  parasites  occurred  especially  in  cach- 
ectic, emaciated  persons,  ultimately  dying  from  diarrhea 
and  dropsy.  The  late  discovery  of  the  worms  he  attributed 
to  the  failure  of  earlier  observers  to  examine  the  intestinal 
mucosa  without  washing  the  adherent  mucus  away  with 
water.  He  described  the  parasites  accurately  as  small, 
bent,  partly  transparent  in  the  fore  part,  partly  yellowish, 
reddish,  or  brown  worms,  with  a  dark  elevated  point  in  the 
middle,  and  the  stomach  filled  with  black  material.  He 
gave  a  clear  description  and  pictures  of  the  microscopic 
features,  especially  the  rounded  mouth  with  four  curved 
booklets  rising  from  conical  elevations,  the  flask-shaped 
esophagus,  the  blunt  tail  of  the  female,  the  fan-like  tail  of 
the  male  inclosing  the  genitalia.  He  proposed  the  name 
agchylostoma — from  ay/Mo^^  bent,  and  Troim,  mouth.  The 
other  details  do  not  seem  necessary  to  cite  now.^ 

Though  Dubini  thought  he  had  discovered  a  new  worm, 
he  had  been  anticipated  to  a  certain  extent.  In  1782  Goeze 
discovered  some  worms  in  the  intestine  of  a  badger  (Meles 
taxus).  Although  he  gave  it  the  name  ascaris  criniformis 
(on  account  of  its  hair-shape),  he  suspected  it  belonged  to  a 
different  genus  from  the  ordinary  ascaris.  He  saw  the 
membranous  expansion  of  the  tail  of  the  male,  and  in  it  two 
rib-like  structures,  which  he  called  hooks. 

In  1789  Frolich  found  similar  worms  in  the  intestines  of 
foxes.  He  also  observed  the  membranous  expansion  and 
hooks,  and  proposed  the  name  hookworm  (Haakenwurm) 
or  uncinaria  for  the  genus.  The  fact  that  other  members 
of  the  family  strongylidse  possess  similar  ''hooks"  in  the 
bursa  does  not  interfere  with  the  retention  of  the  name. 

Dubini,  besides  describing  the  caudal  hooks,  noted  the 
hook-like  teeth  and  the  bent  shape  of  the  body.     As  Stiles 


1  Dubini  was  ill  advised  in  the  construction  of  the  new  word.  In  trans- 
lating from  the  Greek  he  should  have  changed  the  v  to  n  and  the  k  to  c  for 
Italian  usage.     In  other  languages  the  <  would  be  c,  ch,  or  k. 


22  HOOKWORM  DISEASE. 

well  points  out,  the  feature  that  led  to  the  common  name 
was  the  result  of  a  misinterpretation;  the  "hooks"  in  the 
mouth  are  not  present  in  all  species,  and  the  curvature  of 
the  body  is  not  always  distinct,  hut  nevertheless  the  com- 
mon name  is  likely  to  be  retained  by  reason  of  the  rules  now 
followed  in  zoologic  nomenclature. 

Von  Siebold  (1845)  gave  the  parasites  a  place  in  zoology 
among  the  strongylidai.  Castiglioni  and  Pruner  soon  after 
described  the  occurrence  of  the  worms  in  the  bodies  of 
dropsical  and  cachectic  individuals,  but,  like  Dubini,  did 
not  realize  the  actual  relations.  Bilharz  (1853)  and  Gries- 
inger  (1854)  in  Egypt  recognized  the  relation  of  the  para- 
sites to  the  extremely  prevalent  "Egyptian  chlorosis,"  the 
cause  of  more  than  one-quarter  of  all  deaths  in  that  country. 
But  although  Griesinger  especially  was  emphatic  in  his 
statements,  practically  no  attention  was  paid  to  them  for 
more  than  ten  years.  In  1866  Wucherer,  in  Bahia,  again 
called  attention  to  the  subject,  based  upon  its  frequency 
among  negro  slaves  in  Brazil.  His  statements  were  con- 
firmed by  other  Brazilian  physicians,  and  gradually  reports 
began  to  appear  from  various  other  tropical  regions.  In 
Italy  many  additions  to  the  knowledge  of  the  occurrence  of 
hookworms  were  made,  the  most  important  being  the  sug- 
gestion by  Paletti  and  Maliverria  (1877 — 1878)  that  the 
anemia  of  brick  workers,  long  known  in  Italy,  was  caused 
by  hookworm,  and  the  discovery  by  Grassi  (1877)  and 
Parona  of  the  diagnostic  value  of  the  ova  in  the  feces  of 
hookworm  subjects. 

The  migratory  habits  of  Italian  laborers  led  to  a  striking 
epidemic  of  hookworm  disease.  In  the  digging  of  the  St. 
Gothard  tunnel  (1879 — 1880)  a  large  number  of  workmen 
showed  signs  of  intense  anemia.  Perroncito  and  Toncato, 
Bozzolo,  rV)loniiatti,  Parona,  Sonderegger,  and  others 
showed  that  not  only  did  the  parasites  occur  in  the  anemic 


DEFINITION.  23 

cases,  sometimes  in  enormons  numbers,  but  that  they  were 
often  the  only  discoverable  canses  of  disease.  These  re- 
sults were  confirmed  in  other  places,  notably  in  Switzer- 
land, liy  Immermann  and  others,  and  in  Freiburg  by  Banm- 
ler  in  tunnel  workmen. 

These  discoveries  led  to  -  the  proof  that  the  so-called 
''miners'  anemia,"  ascribed  to  deprivation  of  light  and  air, 
in  the  mines  of  France  and  Hnngar}^  was  also  due  to  hook- 
worms, and  in  the  mines  of  Sardinia  measures  to  check  the 
development  and  spread  of  hookworm  eggs  were  followed 
by  diminution  in  the  number  of  cases  of  anemia. 

The  conclusions  regarding  miners'  anemia  were  rapidly 
extended  to  other  countries.  In  1869  Leuckhart  thought 
ankylostomiasis  did  not  occur  north  of  the  Alps.  In  1882 
it  was  discovered  in  brick  workers  in  the  Ehine  country, 
who  had  no  relation  to  Italian  workmen.  In  fact,  the 
anemia  of  the  brick  workers  in  the  Ehineland  and  Prussia 
had  been  recognized,  but  not  correctly  explained,  for  more 
than  twenty  years  before.  The  prevalence  of  hookworm 
disease  in  the  region  of  Cologne  gave  Leichtenstern  oppor- 
tunities for  making  some  of  the  most  important  contribu- 
tions to  the  subject,  including  the  discovery  of  the  disease 
among  the  Belgian  miners  ("Walloons"),  who  worked  in 
the  coal  mines  of  Mons,  Liege,  etc.,  in  winter  and  in  the 
Rhenish  brick  fields  in  summer. 

It  does  not  seem  necessary  to  describe  the  discovery  of 
hookworms  in  various  parts  of  the  tropics.  The  present 
conditions  there  will  be  mentioned  in  the  next  chapter. 
Suffice  it  to  say  that  the  evidence  points  to  the  tropics,  and 
especially  Africa,  as  the  original  home  of  the  disease.  It 
is  not  easy  to  trace  the  routes  the  parasites  followed  to 
Europe,  but  it  is  liiuhly  proliable  they  entered  from  Egypt 
by  way  of  Italy  or  Hungary,  and  spread  from  there  to  Swit 
zerland,  the  Rhine,  and  Belgium,  from  Hungary  to  Ger- 
many, and  from  various  parts  of  the  tropics  to  Cornwall, 


-^  HOOKWORM  DISEASE. 

The  history  of  hookworm  disease  in  the  United  States  is 
of  great  interest.  From  an  early  period  reports  were  pub- 
lished on  the  dirt  eating  and  anemia  of  negroes  in  several 
southern  states,  and  Hirsch  (1883)  and  other  European 
writers  based  upon  these  reports  the  statements  that  hook- 
worm disease  existed,  "although  only  in  slight  extent, 
among  the  negro  population  of  some  parts  of  the  southern 
United  States."  That  Hirsch  does  not  deserve  particular 
credit  for  the  accuracy  of  his  statement  appears  from  the 
fact  that  he  thought  there  was  little  hookworm  disease  in 
Asia. 

It  is  worth  while  recalling  some  of  the  early  American 
accounts,  for  from  these  it  is  obvious  that  the  disease  ex- 
isted, but  the  accurate  diagnosis  was  not  to  be  expected  at 
the  time,  as  the  presence  of  hookworms — in  many  cases 
even  intestinal  worms  in  general — was  not  suspected,  and 
the  significance  of  the  disease  was  wholly  missed. 

Stiles  quotes  Joseph  Pitt  (1808)  as  the  earliest  author 
he  has  found  to  refer  to  the  disease  in  this  country.  Pitt 
described  dirt  eating  among  the  poor  white  people  and 
negroes,  and  thought  it  was  due  to  deficiency  of  nourish- 
ment. The  author  most  frequently  quoted  abroad  is 
Chabert  (Eeflexions  medicales  sur  la  maladie  Spasmodico- 
lyperienne  des  Pays  Chauds,  vulgairement  appelee  Fievre 
Jaune.  J.  L.  Chabert,  Dr.  en  med.  de  la  Fac.  de  Mont- 
pellier,  a.  m.  ord.  des  arm.  Franc,  etc.,  Nouvelle-Orleans, 
de  Pimp,  de  PAmi  des  lois.  1821).  He  referred  to  dirt  eat- 
ing as  a  habit  contracted  by  many  slaves,  and  described  the 
resulting  lesions  and  the  means  of  recognizing  and  curing 
them.  His  words  are  worth  quoting  more  fully  (p.  188 
etseq.):  ''For  most  of  the  negroes,  doing  nothing  is  the 
supreme  bliss.  Some  of  them  carry  love  of  idleness  to  such 
a  point  that  they  employ,  in  order  to  escape  work,  every 
means  suggested  by  sloth,  notwithstanding  the  certainty 


DEFINITION.  25 

of  injury  to  health.  Among  these,  earth,  the  internal  use 
of  which  causes  a  species  of  poisoning,  is  most  common  of 
all,  if  I  may  judge  by  my  own  practice.  Under  the  influence 
of  this  bizarre  food  there  develops  in  those  who  use  it  symp- 
toms and  accidents  like  those  produced  by  poison  in  the 
living  organism — i.  e.,  yellow  complexion,  dry  scaly  skin, 
puffy  face,  swelling  of  the  legs,  engorgement  of  the  abdom- 
inal viscera,  atrophy  of  the  muscles,  palpitation,  dyspnea, 
and  at  last  obvious  signs  of  aneurism  (i.  e.,  dilatation)  of 
the  heart  from  thinning  of  its  walls,  which,  when  well 
marked,  always  ends  the  case." 

Chabert  made  an  autopsy  in  the  case  of  a  dirt  eater,  but 
described  no  worms,  and  thought  a  perforation  he  found  in 
the  stomach  was  due  to  an  old  ulcer.  It  can  hardly  be 
doubted  that  he  was  dealing  with  genuine  cases  of  hook- 
worm disease,  but  wholly  unaware  of  the  fact. 

Geddings,  in  1834,  doubtless  saw  cases  in  the  anemic 
and  cachectic  ''sand  lappers"  of  Carolina.  Little,  in  1845, 
gave  an  interesting  account  of  dirt  eaters  in  Florida,  in 
which  the  descriptions  of  the  subjects  leave  no  doubt  they 
had  hookworm  disease.  Sir  Charles  Lyell  (1849)  also  made 
observations  during  his  travels  in  the  South,  and  noted 
cases  of  dirt  eating  in  Alabama. 

James  B.  Duncan  (Eeport  on  Topography,  Climate,  and 
Disease  of  the  Parish  of  St.  Mary,  La.,  Southern  Medical 
Reports,  edited  by  E.  D.  Fenner,  New  Orleans  and  New 
York,  vol.  1,  p.  190,  1849)  gave  a  very  accurate  description 
of  cases.  He  speaks  of  a  very  common  anemia  among 
negroes  on  plantations,  "very  often  attributed,  and  perhaps 
justly  so,  to  the  pernicious  habit  of  dirt  eating.''  The 
proportion  of  severe  cases  was  not  large.  Duncan  says  (p. 
194):  ''Almost  every  large  plantation  has  three  or  four, 
and  sometimes  more.  Until  the  vital  powers  of  the  system 
are  beginning  to  be  undermined,  no  marked  symptoms  of 


26  HOOKWORM  DISEASE. 

the  disease  being  visible  to  the  ej^e  of  the  planter,  they  are 
generally  suspected  of  laziness  or  malingering.  After  this 
condition  has  existed  for  some  time,  the  skin  presents  a 
paler  hue  than  natural,  or,  if  the  subject  is  a  mulatto,  an 
ashy  white;  the  lips,  tongue,  lining  membrane  of  the  mouth, 
and  palms  of  the  hands  white,  lacking  the  reddish  tinge  of 
health;  the  legs  edematous;  abdomen  distended;  pulse  full, 
soft,  and  frequent;  action  of  the  heart  violent;  if  blood  is 
drawn,  it  is  pale  and  watery;  respiration  on  the  slightest 
exertion  anxious  and  hurried;  in  fine,  all  the  symptoms  that 
characterize  chlorosis  in  females.  We  find  this  condition 
of  things  in  subjects  of  both  sexes.  Many  of  these  cases 
are,  doubtless,  produced  and  aggravated  by  the  deleterious 
habit  of  dirt  eating.  But  I  never  heard  a  negro  admit  that 
he  was  addicted  to  the  habit.  Some  admit  that  formerly, 
3^ears  ago,  they  ate  dirt,  but  do  not  now;  and  others,  trusty, 
truth-telling  negroes  on  all  other  subjects,  on  this  will  lie 
most  pertinaciously  to  the  last,  unless  detected  in  the  act." 
Duncan  thought  that  in  many  cases  "dirt  eating  was  a 
symptom  only  of  a  diseased  condition  of  the  digestive 
organs  and  of  the  system  generally.  With  them  dirt  eating 
is  the  same  propensity  to  which  white  females  resort  to  re- 
lieve a  disordered  acid  condition  of  the  stomach  by  eating- 
quantities  of  chalk,  magnesia,  etc.  This  condition  of  sys- 
tem is  often,  in  my  opinion,  produced  by  a  deficiency  of 
suitable  nutriment.  The  diet  of  negroes  on  most  planta- 
tions being  mostly  salt  pork,  corn  bread,  and  molasses — 
rarely  eating  fresh  meat  and  vegetables — a  condition  of  the 
system  is  thus  produced  closely  allied  to  scurvy."  (He 
noted  spongy  gums,  and  functional  and  organic  disease  of 
the  heart.)  Duncan  reported  cures  by  the  use  of  nutritious 
foods,  fresh  meats,  vegetables,  and  greens,  porter  and  wine, 
iron,  stomaoliics,  and  tonics,  laxatives  when  indicated,  and 
out-door  exercise.     He  throws  a  curious  light  on  the  seri- 


DEFINITION.  27 

ousness  of  the  condition  so  briefly  described  by  speaking  oi: 
the  use  of  tin  masks,  iron  gags,  and  chaining  to  the  floor  to 
correct  dirt  eating.  ''By  nsing  these  means,"  he  says,  "it 
is  true  the  habit  can  not  be  indulged  in,  but  the  cause  that 
produced  the  propensity  still  exists.  Restore  the  healthy 
tone  of  the  system,  invigorate  the  subject,  put  rich  blood 
into  his  veins,  clothe  him  well,  feed  him  well,  and  do  not 
overtask  him;  arouse  his  feelings  of  pride,  teach  him  to  feel 
that  he  is  a  reasonable  being,  and  in  a  majority  of  cases 
success  will  attend  our  efforts,  and  we  shall  have  the  satis- 
faction of  rescuing  a  valuable  servant  from  the  grave." 

It  is  impossible  to  tell  how  much  of  this  belief  was 
founded  on  actual  treatment.  It  may  be  that  mild  cases 
then  improved  without  direct  causal  treatment,  but  it  is 
difficult  to  imagine  that  reinfection  did  not  occur. 

Heusinger  wrote  an  interesting  work  on  dirt  eating 
(''Die  sogenannte  Geophagie  ocler  Tropische — besser, 
Malaria — chlorose  als  Krankheit  aller  Lander  und  Klimate, 
dargestellt  von  C.  F.  Heusinger,  Cassel,  1852),  but  showed 
great  lack  of  critical  insight.  He  asserted  dirt  eating  was 
common  also  in  the  region  of  the  great  lakes,  based  largely 
on  statements  of  Bartlett,  Wood,  and  Drake.  He  properly 
considered  dirt  eating  a  symptom  and  not  a  cause  of  disease. 

Xone  of  these  writers  give  the  impression  they  were 
dealing  with  a  widespread  disorder.  This  is  probably  due 
to  the  fact  that  then,  as  now,  many  negroes  were  immune  to 
the  severe  effects  of  the  infection,  that  the  white  population 
was  scattered  and  was  relatively  small,  and  many  of  the 
whites  probably  escaped  infection.  None  of  the  medical 
writers  we  have  consulted  speak  as  if  the  disease  was  com- 
municable, but  we  liave  found  a  suggestive  statement  in  the 
account  of  an  excellent  lay  writer,  Mr.  Thomas  Affleck,  of 
Washington,  Miss.,  author  of  the  "Southern  Eural  Alma- 
nac," who  had  been  an  extensive  planter,  and  wrote  an  in 


-S  HOOKWORM  DISEASE. 

teresting  chapter  for  Fenner's  "Southern  Medical  Ee- 
ports"  (vol.  2,  p.  429—436,  1851)  "On  the  Hygiene  of  Cot- 
ton Plantations  and  the  Management  of  Negro  Slaves. ' '  He 
confirms  what  others  say  of  the  diet:  "The  general  allow- 
ance of  m^at  being  three  and  a  half  to  four  pounds  per 
week  of  sound  mess  pork,  or  its  equivalent  in  bacon,  to  each 
working  hand  over  10  years  old,  with  bread,  hominy,  vege- 
tables, etc.,  ad  libitum.  Fish  and  molasses  are  given  occa- 
sionally. Not  nearly  enough  of  vegetables  are  grown  and 
fed  to  negroes."  He  also  said  (p.  433):  "Dirt  eating  is 
frequent  among  young  negroes,  and  always  kills  them  if  not 
cured.  The  constant  use  of  molasses  is  said  to  induce  it, 
but  I  can  not  say  how  correctly.  Those  under  the  best  care 
are  liable  to  it.  Seems  to  be  occasioned  by  a  morbid  state 
of  the  stomach,  and  should  be  so  treated.  One  dirt  eater 
upon  a  plantation  will  infect  tJie^ivJiole.  Mostly  infected  at 
from  two  to  ten  year's.  Say,  one  child  in  forty  eats  dirt." 
[Italics  ours. — D.  and  B.] 

On  the  whole,  the  reports  from  the  South  in  the  first  half 
of  the  nineteenth  century  could  not  easily  convince  one  that 
ankylostomiasis  existed  there,  and  in  the  latter  half,  for  a 
long  time,  no  accurate  observations  seem  to  have  been 
made.  Moreover,  during  this  part  malaria  acquired  a  new 
interest  and  importance,  so  that  its  occurrence  was  easily 
exaggerated. 

In  1886  Dr.  Joseph  Leidy  made  an  interesting  remark 
apropos  of  some  specimens  from  anemic  cats  sent  by  Bel- 
field,  of  Chicago.  He  noted  the  worms  had  the  same  struc- 
ture of  mouth  as  had  ankylostomum  duodenale;  thought 
they  might  be  able  to  infect  man,  and  be  one  of  the  previ- 
ously unrecognized  causes  of  pernicious  anemia.  This  idea 
had  been  expressed  before,  and  was  then  repeated  more  or 
less  distinctly  by  various  writers  for  the  next  ten  years. 
In  1891  Dolley  called  the  attention  of  American  physicians, 


DEFINITION.  29 

especially  those  of  the  southern  states,  to  the  "fact,"  an 
per  Hirsch,  that  ankylostomiasis  was  long  since  reported  in 
the  South. 

In  1893  Blickhahn,  of  St.  Louis,  reported  a  case  in  the 
person  of  a  brickmaker  from  Oberhausen,  near  Essen,  in 
Westphalia.  In  1897  Mohlau  reported  several  cases  in 
Buffalo,  and  it  seemed  that  some  of  the  patients  became 
infected  in  this  country  from  Italian  or  Polish  immigrants. 
Through  the  courtesy  of  Dr.  Joseph  Collins,  Dock  was  able 
to  cite  a  case  observed  in  New  York  by  Dr.  Joseph  Frankel 
in  the  person  of  a  foreigner  who  had  long  lived  in  the 
United  States,  and  seemed  to  have  acquired  the  disease 
here,  "perhaps  handling  hides."  (Article  on  Anchylosto- 
miasis,  Loomis  and  Thompson's  System  of  Practical  Medi- 
cine, vol.  3,  p.  337  et  seq.;'1898. ) 

To  this  transition  period  belong  the  reports  of  Herff 
(1894),  who  found  worms  in  a  Mexican  and  asserted  their 
existence  in  this  country;  Dabney  (1898)  and  Tebault 
(1899),  who  both  found  them  in  New  Orleans;  Gray  (1901), 
who  found  them  in  Richmond,  Va.;  Clay  tor  (1901)  in  Wash- 
ington, D.  C;  and  Boston,  Allyn,  and  Behrend  (1901)  in 
Italians  in  Philadelphia;  Dyer  in  St.  Louis;  and  Hall  and 
Yates  in  Baltimore. 

The  era  of  productive  discovery  begai]  at  the  same  time. 
Allen  J.  Smith,  in  1895,  found  ova  of  hoo  kworm  in  the  feces 
in  a  water  closet  in  Galveston,  Texas,  bul  could  not  fix  upon 
the  individual  from  whom  they  were  derived.  On  Feb- 
ruary 17,  1901,  Dr.  Smith  recognized  ova  in  the  stools  of  a 
sailor  born  in  Melbourne,  Australia,  who  first  became  ill 
while  acting  as  overseer  of  a  plantation  in  southern  Mexico, 
where  there  was  an  epidemic  disease  of  a  very  fatal  type, 
which  led  to  pallor,  emaciation,  and  dropsy.  The  patient 
also  had  amebic  dysentery.  Dr.  Smith  recognized  differ- 
ences in  the  worms  expelled  from  the  patient  as  compared 


30  HOOKWOKM  DISEASE. 

w 

witli  ankylo stoma  dnodenale,  and  thought  they  might  be 
uncinaria  stenocephala  of  dogs.  Q^he  dogs  in  the  labora- 
tory, however,  had  only  uncinaria  canina,  so  that  compari- 
sons conld  not  be  made.  Later,  Charles  Wardell  Stiles 
showed  the  existence  of  a  new  si^ecies  in  man,  and  Dr. 
Smith  was  able  to  demonstrate  that  his  patient  had  both 
old  world  and  new  world  hookworms.  Stiles  had  for 
years  pointed  ont  the  probability  of  the  frequent  occur- 
rence of  hookworm  in  America.  In  1901  he  published  his 
views  {Texas  Medical  Neivs,  July),  stating  that  hookworm 
in  man  must  be  more  or  less  widespread  in  the  United 
States.  Soon  after  that.  Smith's  case  was  i3ublished  by 
Dr.  Charlotte  Schaeffer,  who  also  mentioned  the  finding 
of  ova  in  the  feces  of  two  (later  increased  to  eight)  out 
of  eighty-odd  medical  students  in  the  Galveston  school. 
Stiles  (1903)  shows  clearly  the  great  value  of  Smith's  work 
in  the  development  of  our  knowledge  of  hookworm  in  the 
United  States.  "To  the  clinician  it  did  not  mean  ver}^ 
much,  since  no  record  existed  that  the  students  exhibited 
any  very  severe  symptoms.  To  the  zoologist,  however,  it 
meant  a  practical  demonstration  that  uncinariasis  was  more 
or  less  common  in  the  South.  Here  were  eight  students  in 
a  city  (Galveston);  the  chances  that  the  infection  took 
IDlace  in  Galveston  did  not  seem  very  great;  as  the  students 
came  from  different  places,  the  infection  must  be  more  or 
less  widespread;  and,  since  light  cases  occurred  among 
medical  students,  heavier  infections  must  naturally  occur 
among  persons  who  come  more  regularly  in  contact  with 
the  dirt." 

From  a  study  of  the  worms  in  the  case  of  A.  J.  Smith  and 
Claytor,  and  some  from  Porto  Rico,  Stiles  was  able  to  show 
that  they  were  not  uncinaria  stenocephala  or  any  other 
known  species,  and  on  May  10,  1902,  he  described  a  new 
species,  uncinaria  Americana.     In  a  paper  piiblisliod  in  the 


DEFINITION.  31 

Eigliteentli  Annual  Eeport  of  the  Bureau  of  Animal  Indus- 
try (September  25,  1902)  lie  declared  there  was  an  endemic 
of  hookworm  in  the  United  States  which  had  been  generally 
overlooked.  In  the  months  between  the  statements  both 
Claude  A.  Smith  and  H.  F.  Harris  had  reported  cases  in 
Georgia,  and  a  little  later  Harris  made  the  important  asser- 
tion that  the  greater  number  of  cases  of  anemia  in  certain 
southern  states  were  due,  not  to  malaria,  as  universally  be- 
lieved, but  to  uncinariasis,  and  that  it  was  "the  most  com- 
mon of  all  the  more  serious  diseases  of  the  entire  South. 
In  no  other  disease  does  the  victim  suffer  so  long,  in  no 
other  condition  is  he  for  such  a  period  a  menace  to  those 
about  him,  and  in  no  other  malady  of  such  gravity  is  treat- 
ment so  rapidly  and  surely  successful."  W.  F.  Arnold 
complains,  with  justice,  that  the  subject  was  neglected  after 
the  striking  announcements  just  described.  Some  of  the 
subsequent  communications  will  be  referred  to  in  the  next 
chapter. 

The  work  of  Bailey  K.  Ashford  and  his  colleagues  on 
hookworm  disease  in  Porto  Rico  furnishes  one  of  the  most 
interesting  and  instructive  chapters  in  the  history  of  en- 
demic disease. 

In  1899,  soon  after  a  destructive  hurricane  in  the  island, 
Ashford  established  a  hospital  for  the  care  of  those  who 
could  not  be  accommodated  in  the  hospital  at  Ponce,  "Ful- 
ly three-fourths  of  those  admitted  were  suffering  from 
anemia,  which  was  then  believed  to  be  due  to  faulty  diet, 
but,  as  iron,  arsenic,  and  full  diet  failed  to  cure,  it  was 
attributed  to  malaria,  climate,  lack  of  hygiene,  etc.,  all  of 
which  proved  upon  investigation  to  be  inadequate."  In 
studying  the  blood  as  an  aid  to  exact  diagnosis,  Ashford 
was  struck  by  the  high  eosinophilia.  He  suspected  ankyl- 
ostoma,  and  "examination  of  feces  made  the  suspicion  a 
certaintv."     R.  Blanch ard  had  concluded  that  the  disease 


32  HOOKWORM  DISEASE. 

was  present  in  Porto  Rico,  but  no  exact  observations  had 
been  published  and  no  immediate  general  attention  fol- 
lowed Ashford's  first  report,  though  it  had  official  recog- 
nition. 

In  1902  Drs.  Ashford  and  King  made  a  further  study  of 
ankylostomiasis,  and  reported  on  one  hundred  cases  in 
1903.  {American  Medicine,  September  5  and  12.)  This 
aroused  much  interest,  not  only  in  medical  circles,  but  also 
in  the  administration  of  the  island.  In  1904  a  commission 
was  formed  for  the  study  and  treatment  of  anemia,  consist- 
ing of  Dr.  Ashford,  Captain  and  Assistant  Surgeon,  U.  S. 
A.;  Dr.  W.  W.  King,  Past  Assistant  Surgeon,  Public  Health 
and  Marine  Hospital  Service;  and  Dr.  Pedro  Grutierrez, 
health  officer  of  Bayamon.  With  comparatively  slender 
resources  this  commission  carried  out  an  immense  cam- 
paign of  diagnosis,  treatment,  and  scientific  research.  It 
proved  beyond  question  that  the  anemia  so  prevalent  in  the 
island  was  only  a  symptom  of  uncinariasis,  which  affected 
the  rural  population  to  the  extent  of  90  percent.  Still  more, 
it  published  most  valuable  reports  upon  the  work,  and 
upon  hookworm  disease  in  general.  (Report  of  the  Com- 
mission for  the  Study  and  Treatment  of  '' Anemia"  in  Porto 
Rico.     San  Juan,  P.  R.,  1904  et  seq.) 

Even  before  the  time  the  parasites  were  receiving  so 
much  attention  in  America,  Looss  (1898),  in  Cairo,  Egypt, 
made  the  important  discovery  of  the  penetration  of  the 
skin  by  the  larvae,  a  discovery  that  has  made  the  pathology 
and  especially  the  prevention  of  the  disease  much  more 
exact  than  it  was  before.  This  part  of  the  history  will  be 
discussed  in  connection  with  the  ''Modes  of  Infection." 


CHAPTER  II. 

DISTRIBUTION  AND  ECONOMIC  IMPORTANCE. 

Hookworms  have  an  extensive  range,  being  fonnd  in  all 
parts  of  the  tropics,  where  they  may  be  said  with  truth  to 
be  the  greatest  enemies  of  the  human  race,  and  in  many 
countries  with  subtropical  climate,  as  well  as  in  some 
regions  properly  classed  as  temperate.  The  extreme  range 
of  latitude  is  from  51°  N.,  or  the  latitude  of  Belgium,  to 
nearly  40°  S.  Altogether  it  is  one  of  the  commonest  dis- 
orders, and  in  the  tropics  one  of  the  most  important.  It  is 
in  all  j)robability  the  chief  cause  of  the  so-called  tropical 
anemia,  which  has  been  looked  upon  as  due  to  climatic  con- 
ditions rather  than  disease  factors  in  the  usual  sense. 

In  Europe  the  disease  has  been  found  chiefly  in  Belgium, 
France,  England,  Germany,  Hungary,  the  Balkan  peninsula, 
and  Italy.  In  Italy,  Sicily,  and  Sardinia,  where  ankylos- 
tonia  was  first  discovered  as  a  human  parasite,  it  occurs  in 
various  parts  and  sometimes  in  great  intensity.  Previtera 
found  75  percent  of  miners  infected  in  Catania,  in  a  district 
(Muglia)  where  almost  100  percent  had  oxyuris.  In  Spain 
it  occurs  in  miners,  and  probably  other  classes  also. 

In  Austria,  Hungary,  the  plains  of  the  Danube  and 
Theiss,  Servia,  and  Bulgaria  it  occurs,  especially  in  the 
mining  regions,  but  also  elsewhere  and  in  other  classes  of 
the  population.  In  some  parts  of  Hungary  up  to  95  per- 
cent of  miners  have  been  found  infected,  but,  owing  to 
precautions  taken  and  treatment,  this  has  been  reduced  to 
about  30  percent.  Many  are  so  severely  affected  that  they 
are  unable  to  work  on  account  of  swelling  of  the  feet  and 
shortness  of  breath.     The  great  lieat  in  many  Hungarian 

33 


34  HOOKWOEM  DISEASE. 

mines,  up  to  104° — 113°  F.,  favors  the  development  of  the 
larvae. 

In  Belgium  the  disease  has  been  very  prevalent  in  the 
last  quarter  of  a  century.  The  parasites  were  first  discov- 
ered in  Belgium  by  Firket  in  1884,  but,  as  said  before,  the 
disease  probably  existed  among  miners  long  before  that. 
It  was  reintroduced  by  miners  from  St.  Gothard  and  be- 
came epidemic  about  1884,  but  subsided  apparently,  only 
to  break  out  afresh  in  a  most  virulent  form,  with  a  high 
death  rate.  Little  attention  was  paid  at  first,  but,  after  it 
became  serious  in  the  mining  districts  of  Liege,  Mons,  and 
Charleroi,  active  measures  for  its  repression  were  begun  by 
the  government.  At  the  International  Congress  of  Miners 
in  1903  it  was  said  that  10,000  miners  in  the  Liege  basin 
were  infected.  So  great  was  the  extent  that  sick  benefit 
societies  had  to  refuse  membership  to  men  working  in  some 
mines,  the  proportion  of  affected  workmen  being  from  25  to 
75  percent,  with  in  some  places  a  very  high  death  rate. 

In  France  the  miners  in  many  localities  are  also  seriously 
infected,  especially  in  Anzin,  Valenciennes,  Lyons,  and  St. 
Etienne  (2  percent),  and  the  Loire  basin  (5  percent). 

In  the  Dolcoath  mines  in  Cornwall,  England,  where  a 
severe  form  of  anemia  had  been  noted  in  the  miners  for 
about  eight  years  previousl}'^,  Boycott  and  Haldane,  in  Octo- 
ber, 1902,  showed  its  occurrence,  and  traced  it  to  miners 
who  had  lived  in  the  tropics. 

Stockman  (1903)  reported  the  case  of  an  infected  miner 
in  Scotland  who  had  been  in  India. 

In  Germany  it  is  especially  in  the  Ehineland  and  West- 
phalia that  the  parasites  abound,  but  many  cases  occur  in 
the  vicinity  of  Berlin  and  a  few  cases  have  been  found  in 
Saxony,  introduced  by  Polish  miners,  and  in  Silesia.  On 
the  Rhine,  Cologne,  Bonn,  and  Aix-la-Chapelle,  and  in 
Westphalia,  Essen,  Dortmund,  and  Bochum  are  important 
foci. 


DISTEIEUTION.  35 

The  possibilities  for  harm  of  the  disease,  outside  of  the 
tropics,  are  well  illustrated  by  the  conditions  in  the  West- 
phalian  mines.  Infection  there  was  brought  about  by  Ital- 
ian, Hungarian,  and  Polish  miners,  and  was  favored  by 
certain  factors.  One  was  the  rapid  increase  of  the  mining 
industry,  which  led  to  the  importation  of  20,000  new  miners 
in  a  single  year.  (In  the  year  1902  there  were  289  mines, 
with  256,000  miners.)  But  the  most  important  cause  was 
the  introduction  of  spraying  the  mines  with  water  for  the 
purpose  of  preventing  explosions  of  coal  dust.  On  Feb- 
ruary 17,  1898,  there  was  a  tremendous  explosion.  On 
July  12,  1898,  regulations  for  spraying  were  passed,  and 
put  into  execution  from  July  1,  1899,  to  January  1,  1900. 
The  effect  of  this  can  be  seen  in  the  following  table  after 
Oliver,  a  slight  decline  being  followed  by  a  notable  increase: 

,^  Number  of       Number  Per 

infected  mines,  of  cases.  fO.OUO. 

1896 15  107  6.4 

1897 31  113  6.2 

1898 23  99  4.9 

1899 26  94  4.4 

1900 40  275  11.7 

1901 63  1,030  40.6 

1902 66  1,355  52.9 

In  1901,  out  of  63  infected  mines,  57  of  them  were  watered, 
and  showed  1,021  cases.  The  other  6  infected  mines  were 
not  watered,  and  gave  only  9  cases.  At  one  time  in  West- 
phalia there  have  been  25,000  cases  of  hookworm  disease. 

In  Africa,  Egypt  (90  percent  in  Cairo,  20 — 30  percent  in 
other  places),  and  the  Mediterranean  countries,  the  east  and 
west  coasts  to  the  Cape,  Uganda,  Mombosa,  Mozambique, 
Zanzibar,  Madagascar,  Mauritius,  and  the  Comoro  Islands 
are  all  infected,  but,  as  Zinn  and  Jacoby  first  pointed  out, 
the  African  negro  races  are  not  so  likely  to  show  severe 
symptoms  as  many  other  races.     In  Cameroon,  Kiilz  found 


'S6  HOOKWORM  DISEASE. 

70  percent  of  the  population  affected,  and,  although  in 
adults  the  symptoms,  especially  anemia,  were  less  marked 
than  in  children,  many  even  of  the  former  had  severe  pal- 
pitation of  the  heart.  The  less  civilized  the  tribe  the 
greater  ^^^  the  extent  of  the  infection.  In  Kimberly, 
Mathias  discovered  the  disease  in  miners  in  1896.  In  the 
Transvaal,  Posnett  found  32  percent  of  native  miners  af- 
fected. 

In  Madeira,  Goldschmidt  discovered  two  foci,  apparently 
due  to  returned  emigrants  from  Brazil.  The  infection, 
severe  at  first,  became  milder. 

In  Asia  there  are  many  severely  infected  areas,  including 
most  of  India,  where  it  was  first  found  in  1879  by  McCon- 
nell  (Calcutta),  China,  Cochin  China,  Burmah,  Siam,  Cey- 
lon, the  Malay  Archipelago,  Java,  Borneo,  Formosa,  and 
Japan.  In  Japan  the  parasites  were  first  found  by  Baelz 
in  1877.  The  infection  is  very  prevalent  among  country 
peoi)le,  but  as  a  rule  not  severe.  Cases  have  been  found  in 
Siberia,  derived  from  the  Japanese.  In  the  tea  gardeners 
of  Assam,  Dobson  found  ova  in  the  stools  of  454  out  of 
574  immigrants  from  all  parts  of  India. 

Manila  and  the  Philippines,  Guam,  Australia,  New 
Guinea,  Fiji,  and  the  Sandwich  Islands  are  also  severely 
affected.  In  Manila,  Strong  found  52  percent  infected 
among  4,016  Philippine  prisoners.  Among  the  returned 
soldiers  are  many  cases,  most  of  whom,  fortunately,  in  re- 
turning to  the  United  States  live  in  places  not  favorable  for 
the  develoj)ment  of  the  larvae. 

In  South  America  the  disease  is  still  very  extensive,  es- 
pecially in  Brazil,  where  Wucherer  and  Lutz  made  such  im- 
portant observations.  It  occurs  also  in  other  parts  of  the 
continent,  as  far  as  Argentine,  and  in  the  islands  along  the 
coast.  Daniels  found  parasites  in  52  percent  of  autopsies 
in  Demerara.  Law  (1908)  found  45  percent  of  the  popula- 
tion infected  in  British  Guinea. 


DISTRIBUTION.  37 

In  Mexico,  Manuel  discovered  the  worms  in  1902  in  the 
southern  states  of  the  republic.  Alvarez  found  none  in  the 
north  (Sonora),  but  some  in  lower  California  and  Sinaloa. 

In  Central  America  the  disease  is  common  in  all  parts, 
especially  in  the  coast  countries  and  the  foot  hills.  Accord- 
ing to  Prowe,  legends  tell  of  its  existence — symptomatic, 
of  course — in  Guatemala  and  San  Salvador  for  centuries. 

In  all  parts  of  the  Antilles  the  disease  is  present.  In 
Cuba  it  was  first  shown  to  exist  by  Agramonte  (1902). 
Guiteras  finds  it  less  prevalent  in  Cuba  than  the  Porto  Rico 
Commission  found  it  in  the  latter  island. 

In  Panama,  in  the  pathological  laboratory  of  the  Ancon 
Hospital,  Whipple  found,  in  autopsies,  old  world  hookworm 
in  17  percent,  the  new  world  variety  in  21  percent  of  bodies. 
In  about  half  the  cases  of  the  latter  the  old  worm  was 
present,  but  necator  Americanus  predominated  in  all  heavy 
infections.  Brem,  in  Panama,  found  hookworms  in  36.1 
percent  of  277  patients  from  various  parts  of  the  tropics. 

United  States. 

No  systematic  investigation  has  been  made  of  the  terri- 
tory known  to  be  infected.  Dr.  C.  W.  Stiles  has  made  sev- 
eral reconnoissances,  including  a  large  part  of  the  South. 
These  have  stimulated  many  valuable  observations  by 
physicians  in  various  parts  of  the  country.  The  extent  and 
the  intensity  of  the  infection  in  the  whole  population  can 
be  surmised  from  the  data  present,  but  a  systematic  and 
extensive  search  is  very  much  needed. 

It  is  clear  that  the  country  from  Virginia,  at  the  Potomac 
river,  to  Florida  and  Texas  is  infected.  In  Virginia,  Clay- 
tor's  early  case  furnished  Stiles  with  the  first  specimen  of 
uncinaria  Americana.  Bagly  (1910)  believes  there  are  80 
percent  of  infected  work  people  in  the  cotton  mills. 


o»  HOOKWOEM  DISEASE. 

In  North  Carolina  the  disease  is  even  more  frequent,  as 
shown  by  the  valuable  work  of  Nicholson  and  Rankin 
(1904).  They  found  that  37  percent  of  140  students  of 
Wake  Forest  University  were  infected,  usually  in  a  mild 
form.  Semetimes  every  man  from  a  given  district  was 
infected. 

In  South  Carolina  the  conditions  are  doubtless  equally 
serious,  as  shown  by  Stiles'  investigation,  but  extensive 
observations  are  lacking. 

In  Georgia  the  assertion  of  Harris  that  the  disease  is  one 
of  the  commonest  of  the  serious  diseases  was  found  justified 
by  C.  A.  Smith  (Atlanta),  Warfield  (Savannah),  A.  G.  Fort, 
and  many  others. 

In  Florida  extensive  observations  do  not  yet  exist,  but 
the  disease  is  frequent,  as  Stiles  pointed  out  in  his  early 
survey.  Kinyoun  (1908)  found  very  many  hookworm  car- 
riers, especially  among  negroes.  At  present  active  efforts 
are  being  made  for  repression  of  the  disease. 

In  Alabama,  Bondurant,  of  ]\robile  (1903),  first  called  at- 
tention to  the  extent  of  the  disease.  Harrison,  of  Talledega 
(1204),  made  an  important  addition  to  our  knowledge. 
Perry  (1910)  reports  15  to  20  percent  in  the  white  popula- 
tion infected,  and  Cole  and  Winthrop  {vide  infra)  show 
even  more. 

In  Mississippi,  Bass  found  from  his  own  observations  and 
those  of  correspondents  that  up  to  50  percent  of  the  popu- 
lation were  affected,  and  concluded  that  practically  all  the 
rural  population  of  the  southern  half  of  the  state  have  or 
have  had  the  infection. 

In  Louisiana,  Lemann  and  Guthrie  called  attention  to  the 
importance  of  the  disease  in  1903,  and  many  cases  have 
been  observed  since  then,  but  no  extensive  series  of  cases 
has  been  reported.  The  conditions  in  country  localities  are 
doubtless  al)ont  the  same  as  in  adjacent  states.     Gage  and 


DISTRIBUTION.  39 

Bass  have  examined  90  students  in  the  Tiilane  University 
who  were  living  in  the  state;  42.4  percent  of  those  from  the 
country,  and  2.5  percent  from  the  city  were  found  infected, 
or  a  total  in  the  whole  state  of  20.7  percent  of  young  male 
adults  were  hookworm  carriers. 

In  Arkansas,  Deaderick  found  comparatively  few  cases, 
and  the  same  will  probably  hold  good  in  Tennessee. 

Texas  is  widely  affected,  as  Allen  J.  Smith  showed  early. 
Investigations  are  now  being  made  by  the  State  Board  of 
Health,  and  fully  confirm  the  wide  range  and  intensity  of 
the  infection. 

Valuable  information  appears  in  a  report  by  Dr.  Stiles 
to  the  Bureau  of  Labor.  (Annual  Eeport  of  the  Surgeon 
General  of  the  Public  Health  and  Marine  Hospital  Service 
of  the  United  States  for  the  fiscal  year  1908,  AYashington, 
1909.) 

The  investigation  shows  that  12.67  percent  of  cotton  mill 
employees  are  hookworm  suspects.  The  percentage  varies 
with  sex  and  age. 

^  Percent 

suspects. 

Over  20   years 8.4 

16  to  20  years 19.2 

Under  16  years    27.2 

Females    16.1 

Males    15.2 

Boys  under  16  years 29.4 

Girls  under  16  years 18.7 

Boys  16  to  20  years 20.7 

Girls  16  to  20  years 18.1 

Males  over  20  years 5.8 

Females  over  20  years 13. 

Interesting  observations  have  been  made  on  recruits  in 
the  United  States  Army.  Siler  (1909),  in  an  examination 
of  105  recruits  from  the  southern  states,  found  93  infected, 
or  88.5  percent,  and  85  percent  in  a  total  of  140  cases. 

Chamberlain  (1909)  found  60  percent  of  infected  men 
among  southern  recruits. 


40  HOOKWORM  DISEASE. 

The  observations  of  Gage  and  Bass  on  296  university 
students  are  interesting  in  comparison  with  those  on  re- 
cruits, for  they  deal  with  young  men  of  about  the  same  age, 
presumably  equally  free  from  obvious  symptoms,  probably 
belonging-sto  families  in  better  circumstances  than  those  of 
the  recruits,  and  not  so  much  exposed  to  the  danger  of  in- 
fected soil.  The  figures  are  small,  but  no  selection  was 
made.  The  number  of  worms  recovered  from  the  subjects 
varied  from  3  or  4  to  200,  so  that  the  men  were  worm  carriers 
of  real  danger  under  conditions  favorable  to  the  dissemina- 
tion and  development  of  the  ova. 

Locality.  Positive.      Negative. 

Alabama   14  19 

Arkansas 4  9 

Florida 1  4 

Georgia  7  7 

Illinois   2 

Kentucky    0  1 

Louisiana,  outsifie  New  Orleans 27  51 

Louisiana,  in  New  Orleans 1  39 

Massacliusetts   1 

Mississippi    14  38 

Missouri    0  3 

Oklahoma   1  3 

Pennsylvania   0  1 

South   Carolina 0  3 

Tennessee  2  6 

Texas   7  7 

Canada  1 

Porto  Rico 1  0 

Roumania 1 

Out  of  the  subjects  from  the  southern  states  outside  of 
New  Orleans  we  get  a  percentage  of  infected  students  of 
32.8. 

Winthrop  and  Cole,  in  examining  66  Alabama  medical 
students,  found  33,  or  50  percent,  infected. 

Further  facts  bearing  on  the  economic  aspects  of  hook- 
worm should  be  noted.     Among  the  females  of  child-bear- 


DISTRIBUTION.  41 

ing  age,  13  to  18  percent  are  uuable  properly  to  iioiirisli  in- 
fants. Of  males  of  military  age,  5.8  to  20.7  percent  are  rel- 
atively inefficient.  Among  children  of  school  age,  18.7 
(females)  to  29.1  (males)  are  miable  properly  to  profit  from 
study.  "Taking  all  the  statistics  together,  12.6  percent  of 
the  mill  population  are  affected  with  a  disease  which 
materially  inhibits  their  normal  working  powers,  and  hence 
inhibits  the  economic  development  of  the  community  in 
which  they  live." 

It  should  also  be  noted  that  in  some  of  the  mills  the  pro- 
portion of  hookworm  cases  is  as  high  as  80  percent  among 
the  children. 

Stiles  has  also  pointed  out  the  part  the  negro  has  in  the 
perpetuation  and  spread  of  hookworm  disease.  Relatively 
immune  to  the  disease,  the  negro  is  an  extensive  worm 
carrier,  and  is  even  more  careless  as  regards  soil  pollution 
than  his  white  neighbor. 

In  general,  the  parasite  found  in  old  world  cases  is  ankyl- 
ostoma  duodenale;  that  in  America,  necator  Americanus; 
but  Leiper  found  the  latter  widely  distributed  in  the  tropics, 
especially  in  Africa.  It  has  been  found  in  returned  immi- 
grants in  Italy,  from  Brazil  as  well  as  from  the  United 
States  (Schifone),  and  also  in  other  localities,  but  appar- 
ently has  not  yet  spread  beyond  the  immigrants.  Necator 
Americanus  has  also  been  found  in  patients  from  various 
parts  of  Asia,  Ceylon,  the  Philippines,  and  Australia,  in 
the  Hamburg  Sailor  Hospital  (Eodenwaldt),  and  by  Noc  in 
Cochin  China.  Looss  found  it  in  pygmies  in  Africa,  and 
Fiilleborn  in  Cameroon.  Da  Silva  Pinto  finds  necator  more 
frequently  in  the  state  of  Sao  Paulo  in  Brazil  than  ankyl- 
ostoma.  Branch  thinks  necator  may  be  the  original  and 
more  common  tropical  hookworm.  The  conditions  of  work 
and  travel  at  the  present  time  are  such  as  to  cause  even 
greater  mingling  of  the  two  species  than  occurs  now. 


42  HOOKWORM  DISEASE. 

Climate. 

Tlie  chief  factors  in  the  existence  of  hookworm  infection, 
given  the  j)resence  of  the  parasite,  as  by  fresh  importation, 
are  high  temperature  and  moisture.  The  extent  of  the 
disease  in  fhe  tropics  makes  this  clear,  and  the  intensity  of 
the  disease  in  the  tropics  even  clearer.  Outside  the  tropics, 
mines  offer  the  best  conditions  for  the  disease  to  exist.  Xot 
all  mines  are  equally  affected,  even  when  miners  carrying 
worms  are  employed.  In  the  mines  of  Pas-de-Calais,  for 
exami)le,  Brehon  found  only  two  infected  miners,  and  they 
had  come  from  a  mine  near  Mons,  in  Belgium.  The  mines 
at  Pas-de-Calais  have  neither  high  temperature  nor  great 
moisture.  So  also  in  Bohemia  no  cases  were  found  until 
1903,  and  since  then  only  a  few.  But  the  mines  are  not 
very  deep  and  the  temperature,  accordingly,  not  very  high. 
Wainwright  and  Nichols  (1904)  made  a  large  series  of 
observations  in  the  anthracite  coal  mines  of  Pennsylvania, 
but  found  hookworm  in  only  one  case. 

Tenholt  gives  an  instructive  table  showing  the  relation 
of  temperature  in  mines  to  infection  in  Westphalia. 


TPinnpratiirp  Number  of        Percentage 

lempeiaiuie.  workmen.  of  infected. 

Below   17°C.=62.6°F.    .  , 36,033  0.6 

17°— 20°C.=62.6°— 68°F 68,604  0.4 

20°— 22°C.=68°— 71.6°F 43,710  2.5 

22°— 25°C.=71.6°— 77°F 39,836  11.7 

Above  2.5°C.=77°F 9,853  39.9 

(The  most  favorable  temperature  for  the  development  of 
the  larvge  is  from  25°  to  35°  C,  or  78.5  to  95°  F.  Below  22° 
C.  or  71°  F.  few  ova  develop.) 

The  hot  season  in  countries  with  temperate  climates  may 
assist  in  the  development  of  hookworm  larvae  in  permanent 
or  temjoorary  water  or  in  damp  earth,  but,  owing  to  the 
length  of  time  the  larvfe  require  in  order  to  reach  the  in- 


DISTRIBUTION.  43 

fecting  age,  such  regions  are  rarely  intense  seats  of  the 
disease. 

The  relation  of  moisture  to  hookworm  infection  has  been 
noticed  by  all  who  have  studied  the  disease.  In  the  tropics, 
in  brickyards,  and  in  tunnels  and  mines  (coal,  tin,  salphur, 
gold,  diamond,  etc)  a  certain  degree  of  wetness  of  the  soil 
has  been  found  to  obtain  wherever  the  hookworm  disease 
occurs.  This  agrees  with  facts  regarding  the  life  history 
of  the  parasites,  which  will  be  discussed  in  another  place. 
Turner  explains  the  absence  of  ankylostomiasis  in  certain 
South  African  mines  by  the  acidity,  from  sulphuric  acid, 
of  the  water.  Deep,  warm,  wet,  and  alkaline  mines  are 
especially  affected. 

Stiles  has  shown  that  in  the  southern  states  sandy  soil  is 
more  favorable  than  clay  for  the  production  of  the  disease. 
This  is  probably  due  to  the  fact  that  in  wet  sand  the  larvae 
can  easily  avoid  drying  and  at  the  same  time  obtain  oxygen. 
On  dry  soil  the  larvae  soon  die,  and  among  dwellers  of  such 
places,  as  the  Arabs  of  the  Sahara  desert  and  the  Soudanese, 
the  disease  is  rarely  seen.  Deaderick  has  pointed  out  that 
alluvium  offers  favorable  conditions  for  the  larvae,  and  that 
all  the  ground  conditions  are  not  yet  known.  The  Porto 
Rico  Commission  has  also  shown  that  not  only  alluvium,  but 
also  clay  soils,  offer  numerous  foci,  but  Leichtenstern  could 
find  no  larvae  in  the  clay  of  brickyards.  It  is  important  to 
distinguish  between  pools  of  water  that  may  long  remain 
on  clay  and  earth  free  from  water.  The  life  history  of  the 
larvae  (see  Chapter  III)  will  throw  much  light  on  the 
subject. 

Shade  is  an  important  element,  and  will  have  to  be  con- 
sidered in  connection  with  the  life  history  of  the  larvae  and 
the  modes  of  infection.  Elevation  is  of  no  importance  if 
the  other  conditions  are  favorable;  mountains,  as  the  St. 
Gothard  tunnel,  over  3,000  feet  above  sea  level,  as  well  as 
coast  lands,  are  involved. 


44  hookwoe:m  disease. 

Occupation  and  social  position  of  hookworm  subjects. — 

Hookworms  affect  especially  those  who  have  intimate  re- 
lations to  the  soil.  In  the  tropics  it  is  especially  the  poorer 
classes,  the  agriculturists  and  their  families,  that  are  af- 
fected. According  to  the  Porto  Eico  Commission,  for  ex- 
ample, 85  percent  of  the  nearly  one  million  inhabitants  are 
poor  and  75  percent  are  agriculturists.  "The  poorer  the 
man,  the  more  exposed  is  he  to  heavy  infection.  Coffee 
pickers  and  laborers  on  coffee  estates  are  the  most  exposed 
of  all  laborers  on  the  island.  Infection  on  sugar  planta- 
tions is  not  so  common,  but  is  nevertheless  frequent,  espe- 
cially in  the  irrigating  ditches. ' '  Washing  at  the  edges  of 
streams  and  banana  culture  are  other  occupations  leading 
to  infection.  One  of  us  has  observed  many  instances  in 
charcoal  burners  and  turpentine  "dippers."  The  people 
come  from  infected  regions,  and  their  occupations  offer  fa- 
vorable conditions  for  the  spread  of  the  disease. 

Gardening  is  a  possible  means  of  infection  in  the  well- 
to-do,  as  also  in  j)rofessional  gardeners. 

In  many  regions  outside  the  tropics,  hookworm  disease  is 
rather  a  trade  disease  than  an  endemic.  Mining  and  brick- 
making  have  frequentl}^  been  alluded  to.  The  details  of  the 
mode  of  infection  are  discussed  in  Chapter  IV,  but  it  may 
be  said  here  that  in  many  places  the  wives  and  families  of 
miners  and  brickmakers,  and  sometimes  gardeners,  do  not 
share  the  disease. 

Barefooted  children. — In  certain  occupations  infection 
takes  place  through  the  hand,  the  bare  feet,  or  through  de- 
fective boots.  An  imjoortant  cause  in  the  southern  United 
States  is  the  habit  among  children,  even  of  the  better 
classes,  in  the  country  of  going  barefoot.  Not  only  country 
children,  but  city  children,  in  the  summer  vacations  have 
ground  itch,  and  later  hookworm  disease,  as  we  have  ascer- 
tained in  dozens  of  instances.     Even  adults  oecasionallv  get 


DISTRIBUTION.  45 

infected  by  wading-  in  pools,  yielding  to  what  Claude  A. 
Smith  aptly  calls  "the  joy  of  going  barefoot."  In  heavily 
infected  regions  persons  of  all  kinds  of  classes  and  occupa- 
tions, and  of  all  ages,  occasionally  get  the  disease.  In 
some  of  these  the  method  of  infection  is  obscure.  Dirty 
vegetables  or  fruit,  or  skin  infection  by  larvae-containing 
water,  are  the  most  probable. 


CHAPTER  HI. 

-,  ZOOLOGIC  FEATURES. 

Hookworms  belong  to  the  class  of  nematodes,  the  family 
strongylidae  and  subfamily  strongylinaB. 

The  nematodes  form  a  very  large  class  of  worms,  usually 
long  and  narrow,  from  1  millimeter  to  40  to  100  centimeters 
in  length,  round  on  section,  and  sometimes  hair-like  in  their 
proportions.  The  sexes  are  usually  distinct;  the  males 
usually  smaller  than  the  females,  and  generally  distin- 
guished also  by  the  shape  of  the  tail  end,  which  is  some- 
times rolled  in  a  circular,  spiral,  or  cork-screw  manner; 
sometimes,  as  in  hookworms,  s]3read  out  like  an  umbrella, 
or  funnel-shape.  The  length  of  the  body  is  sometimes 
marked,  as  in  ascaris,  by  four  longitudinal  bands.  There 
are  in  some  species  circular  striations,  and  in  others  the 
bodies  are  smooth,  or  furnished  with  papillae  or  other  ap- 
pendages. The  mouth  end  varies  in  shape  in  different 
genera,  is  generally  narrower  than  the  body  beyond  it,  and 
possesses  six  papillae.  It  passes  into  a  muscular  esophagus, 
that  also  varies  in  shape  and  proportion  in  different  genera, 
and  this  in  turn  is  followed  by  the  chyle-gut  and  the 
rectum,  which  opens  near  the  tail  end  of  the  worm.  The 
nerves  of  nematodes  are  made  up  of  scanty  groups  of  gan- 
glion cells  and  fibers,  especially  well  developed  around  the 
esophagus.  The  parasitic  species  have  no  special  sense 
organs.  Some  free-living  ones  have  two  reddish  eyes,  fur- 
nished in  some  species  with  lenses.  The  excretory  organs 
consist  of  a  system  of  tubes,  ending  in  an  excretory  pore. 
The  genital  organs  are  tubular.  That  of  the  male  opens  in 
common  with  the  rectum,  and  that  of  the  female  is  separate 

4G 


ZOOLOGIC  FEATURES.  47 

from  and  usually  anterior  to  the  anus.  All  male  nematodes 
have  preanal  and  postanal  papillae,  which  are  used  in 
specific  differentiation.  The  eggs  are  so-called  ''simple 
ova,"  containing  only  one  kind  of  cell,  and,  though  varying 
considerably,  are  usually  characteristic  for  each  species. 
Some  species  are  oviparous,  and  others  viviparous.  The 
development  of  nematodes  is  simpler  than  that  of  tape- 
worms or  flukes.  In  many  cases,  as  ascaris,  trichocephalus, 
and  oxyuris,  there  is  no  intermediate  host;  in  others,  as 
dracunculus  and  filaria,  there  is.  In  some,  as  strongyloides, 
there  is  reproduction  outside  the  definitive  host.  In  the 
case  of  hookworms,  as  we  shall  see,  part  of  the  development 
of  the  larvae  takes  place  outside  the  host.  Very  few  nema- 
todes (strongyloides)  reproduce  outside  the  definitive  host. 

Round  worms  live  partly  in  fresh  or  salt  water,  in  earth 
or  mud,  in  decomposing  matter  of  all  kinds,  partly  parasitic 
in  various  organs  of  animals,  and  very  often  in  plants. 
Familiar  examples  are  the  common  intestinal  round  worm, 
ascaris  lumbricoides,  the  "vinegar  eel"  (anguillula  aceti), 
and  the  trichina  spiralis  (trichinella) ;  one  of  the  most  in- 
teresting is  the  "hair-worm"  (gordius),  popularly  sup- 
posed to  develop  from  horse-hair  put  in  water  for  that  pur- 
pose, and  in  rare  cases  found  as  a  parasite  in  man. 

The  nematodes  are  subdivided  into  eight  families: 

1.  Enoplidse.     Live  free;  many  species  in  sea  water. 

2.  Anguillulidae.  Characterized  especially  by  a  double 
swelling  of  the  esophagus  ("rhabditic") ;  live  free,  es- 
pecially in  fresh  water  or  in  earth,  or  in  decomposing 
material  ("vinegar  eels");  many  are  parasites  of  plants, 
and  a  few  of  animals.     Many  are  very  minute. 

3.  Angiostomidae.  Developing  by  heterogeny,  contain- 
ing the  genus  strongyloides. 

4.  Gnathostomidae.  A  small  family,  often  parasitic  in 
wild  animals,  but  very  rarely  in  men. 


48  HOOKWORM  DISEASE. 

5.  Filaridse.  Very  long,  narrow  worms,  represented  by 
several  species  of  important  parasites,  including  filarise. 

6.  Trichotracliilid«.  Containing  several  important  para- 
sites, especially  trichina  (trichinella)  and  tricliocephalus,  or 
the  whipworm,  a  common  parasite  of  man  in  warm  coun- 
tries. 

7.  Strongylidse.  A  very  large  group  subdivided  into 
several  sabfamilies.  Besides  hookworms,  eustrongylus, 
strongylus,  and  sclero stoma  belong  to  this  family. 

8.  Ascaridae.  Containing  the  common  parasitic  round 
worms  and  pinworms,  and  some  others. 

The  strongylidsB  form  a  very  large  family.  They  are 
characterized  by  long,  cylindrical  bodies,  rarely  filiform; 
the  possession  of  six  oral  papillae — two  lateral  and  four 
sub  median — generally  projecting  in  the  form  of  nodules  or 
conical  points;  a  mouth  capsule  with  or  without  teeth, 
either  in  the  body  axis  or  turned  dorsally  or  ventrally.  The 
esophagus  is  more  or  less  swollen  in  the  posterior  part.  The 
males  have  a  "bursa  copulatrix"  and  one  or  two  spicules; 
the  females  have  one  or  two  ovaries.  The  eggs  are  usually 
deposited  in  segmentation,  sometimes  containing  the  em- 
bryo. The  sexes  are  distinct.  Important  members  are  the 
"colic  worms"  of  horses  and  the  kidney  worms  of  hogs  (but 
not  the  kidney  worms  of  dogs  and  man — Stiles),  the  "gape 
worms"  of  chickens,  and  the  hookworms.  Many  others  are 
frecjuent  parasites  of  various  lower  animals,  and  occasion- 
ally of  man.  The  members  of  the  family  have  undergone 
many  changes  of  nomenclature,  not  necessary  to  describe 
fully  in  this  place.  There  is  also  much  difference  of  opinion 
regarding  the  nomenclature  and  classification  of  the  hook- 
worms. The  following  list  shows  some  of  the  most  im- 
portant synonyms  in  chronological  order: 

1789:  uncinaria — Frolich. 

1843:  agchylostoma  dnodoualo — llulnni. 


ZOOLOGIC  FEATURES.  49 

1845:  ancylostoma  duodenal e — Creplin. 
1850:  an cliylo stoma  duodenale — Dubini. 
1851 :  ancylostomum  duodenale — Diesing. 
1851:  strongylus  quadridentatus — von  Siebold. 
1851:  sclerostoma  duodenale — Cobbold. 
1861:  dochmius  anchylostomum — Molin. 
1861:  monodontus — Molin. 
1866:  strongylus  duodenalis — Schneider. 
1876:  dochmius  duodenalis — Leuckart. 
1879:  anchilostoma  duodenale — Bozzolo. 

Ankylostoma  Duodenale. 

The  generic  name  above,  or  ankylostomum  duodenale,  or 
ancylostomum  duodenale  (French,  anchylostome;  German, 
ankylostomum  or  anchylostomum;  Italian,  anchilostoma)  is 
preferred  in  England  and  the  continent  for  the  old  world 
hookworm.  No  matter  how  spelled,  Dubini 's  name  seems 
justified  by  the  accuracy  of  his  description.  The  spelling 
' '  agchylostoma, "  passable  in  Italian,  would  have  to  be 
latinized  for  international  nomenclature,  "ancylostoma" 
being  the  correct  spelling. 

The  name  uncinaria  was  widely  adopted  in  America  by 
reason  of  the  important  work  of  Stiles,  though  Looss  from 
the  beginning  objected  to  the  change  on  account  of  the  fact 
that  the  genus  uncinaria  of  Frolich  agrees  with  the  type 
criniformis  (Goze)  more  than  with  ankylostoma  duodenale 
(Dubini).  More  recently  (1907),  Stiles  states  that  "the 
old  genus  uncinaria  (type  vulpis^  criniformis)  must  be 
divided  into  at  least  four  smaller  groups:  uncinaria  (type 
vulpis),  agchylostoma  (type  duodenale),  necator  (type 
Americanus),  bunostomum  (type  trigonocephalum),  and 
probably  into  several  additional  units.  .  .  .  Evidence 
is  accumulating  to  the  effect  that  they  should  be  given 


50  HOOKWOEM  DISEASE. 

generic  rank."  The  recent  (1909)  classification  of  Railliet 
and  Henry  shows  the  same  tendency.  Besides  the  two 
human  species  of  ankylostoma  and  necator,  there  are  sev- 
eral species  of  the  genus  uncinaria  which  are  found  in 
lower  animals — e.  g. : 

Uncinaria  canina, 

Uncinaria  stenocephala,      tin  dogs. 

Uncinaria  trigonocephala, 

Uncinaria  (ankylostoma)  tubaeformis,  or  ^ 

Uncinaria  perniciosa,  !>in  cats. 

Uncinaria  Balsamoi,  '  J 

Uncinaria  trogocephala,  in  shee^D. 

Uncinaria  radiata,  in  cattle. 

Uncinaria  Lucasi,  in  seals  (thought  by  Looss  to  be  the 
cause  of  the  great  mortality — 17  percent — of  suckling  seals 
on  the  Pribiloff  Islands). 

Uncinaria  os  papillatum,  in  elephants. 

There  is  no  j^roof  that  any  of  these  infect  man,  and  among 
lower  animals  each  genus  infested  seems  to  have  its  own 
species  of  hookworms.  The  worm  supposed  by  Rathonyi  to 
be  a  hookworm  in  mine  horses  in  Hungar}^  has  been  shown 
to  be  a  sclerostoma. 

In  order  to  make  clear  the  anatomic  features  of  human 
hookworm,  it  seems  best  to  describe  at  length  the  one  long- 
est known,  and  to  mention  more  briefly  the  points  of  differ- 
ence in  the  new  world  23arasite.  In  this  we  follow  the 
more  exhaustive  descriptions,  especially  of  Looss,  Stiles, 
and  Allen  J.  Smith. 

The  old  world  hookworms  are  small  and  almost  cylin- 
drical, the  male  about  10  millimeters  long  and  0.45  milli- 
meters wide,  the  female  12  to  18  millimeters  long  and  O.GO 
millimeters  wide.  (Frontispiece.)  In  both  sexes  the  an- 
terior end  tapers  gradually.  In  the  female  the  jDosterior  end 
tapers  to  a  fine  point  or  spine.     (Fig.  1.)     The  posterior  end 


ZOOLOGIC  FEATUKES. 


51 


J— > 


p< 


be 


52  HOOKWORM  DISEASE. 

of  the  male  tapers  in  about  the  last  quarter  of  its  length,  but 
the  tip  of  the  tail  is  concealed  by  the  bursa,  which  flares  out 
to  a  width  equal  to  that  of  the  thickest  part  of  the  body,  or 
even  more,  giving  the  tail  end  a  square  or  sometimes  con- 
cave appea^'ance  at  the  end.  The  color  when  alive  is  some- 
what flesh-red  or  cream  color;  when  dead,  duller,  gray  or 
grayish  white.  The  posterior  two-thirds  are  often  brown 
or  reddish  brown,  from  blood  in  the  intestine.  The  skin  is 
smooth,  delicate,  with  fine  transverse  striations,  AVith  the 
bending  of  the  worm  transverse  folds  are  formed,  especially 
about  the  head.  The  name  hookworm  is  often  supposed  to 
be  due  to  the  bending  of  the  head  backwards,  and  this  is  so 
striking  a  feature  that  the  supposition  is  natural,  though 
the  name  was  given  on  account  of  other  "hooks,"  as  has 
l)een  mentioned  before.  Eight  (Smith) — Looss,  four — mus- 
cular bands,  most  pi ainl}". defined  on  the  sides,  symmetric- 
ally arranged,  run  the  length  of  the  body,  merging  to- 
gether laterally  to  form  a  fairly  continuous  body  wall,  and 
in  the  male  help  to  form  the  bursal  ribs. 

Besides  the  proper  skin  muscles,  Looss  describes  certain 
special  muscles,  such  as  the  anal  muscles,  in  female  worms 
only;  the  vulvar  muscles;  the  cephalo-esophageal  muscles, 
which  pass  from  the  top  of  the  nervous  ring  to  the  surface 
of  the  esophagus,  and,  extending  obliquely  forward  through 
the  bod}^  cavity,  are  inserted  partly  in  the  skin  and  partly 
in  the  mouth  capsule.  They  probably  assist  in  the  move- 
ments of  the  head,  as  well  as  in  those  of  the  buccal  capsule. 
The  end  of  the  chyle -gut  is  surrounded  by  a  network  of 
muscles,  especially  well  developed  in  males.  In  both  sexes 
there  is  a  sphincter  muscle  of  the  rectum.  Finally,  there  is 
a  complicated  system  of  muscles  in  connection  with  the 
tail  end  of  the  male. 

The  body  cavity  is  divided  by  a  membranous  septum  at- 
tached dorso-ventrally,  in  the  folds  of  which,  as  in  a  mesen- 


ZOOLOGIC  FEATITKES, 


Do 


-Ceri^g/.s. 


Fig-.  2.  Male  hookworm  (ankyl- 
ostoma  duodenale)  of  man.  ac.  "p., 
accessory  piece  to  spicules;  a.  p.,  anal 
papilla;  h.  c,  buccal  capsule;  can.  cerv. 
gl.  s.,  canal  of  left  cervical  gland;  cerv. 
gl.  d.,  right  cervical  gland;  cerv.  gl.  s., 
left  cervical  gland;  cu.,  cuticle;  cul., 
cul  de  sac  of  testicular  tube;  e., 
esophagus;  e'.,  posterior  end  of 
esophagus;  e.  p.,  ventromedian  excre- 
tory pore;  ej.  can.,  ejaculatory  canal; 
int.,  intestine;  I.  r.,  lateral  ray  of  bur- 
sa; m.,  muscular  layer;  p.,  lateral 
precaudal  papilla;  sp.,  spicules;  sp'., 
anterior  end  of  spicules;  test.,  testicu- 
lar tube;  ves.  sem.,  vesicula  seminalis; 
V.  v.,  ventral  rays  of  bursa.  Greatly 
enlarged.  (After  Schulthess,  copied 
from  Blanchard. ) 


54 


HOOKWORM  DISEASE. 


tery,  tlie  alimentary  canal  is  supported.  In  tlie  two  divi- 
sions of  the  cavity  are  the  cervical  and  esophageal  glands, 
the  sexual  tubes  and  glands,  and  the  anal  glands.  (Fig.  2.) 
The  alimentary  apparatus  consists  of  the  mouth  and  its 
appendages,  the  esophagus,  and  the  straight  intestinal 
canal,  which  extends  to  the  posterior  end  in  each  sex,  termi- 
nating independently  in  the  female,  but  in  the  male  form- 
ing a  cloaca  with  the  sexual  apparatus. 


Fig.  3.     Dorsal  view  of  anterior  end  of  the  old  world  hookworm   (ankylos- 
toma  duodenale;   of  man.     Greatly  enlarged.      (After  Perroncito.) 


The  mouth  23arts  of  a  hookworm  are  remarkable  and  com- 
plicated, and  furnish  important  features  for  the  specific 
diagnosis  of  the  worms.  The  mouth  in  the  old  world  worm 
Oldens  toward  the  back  of  the  parasite,  on  account  of  the 
dorsal  bend,  so  tliat  the  rini  of  the  mouth  is  nearly  or  cpiite 
parallel  to  the  long  axis  of  the  l)ody  of  the  worm.  (Fig.  1.) 
Tlie  mouth  capsule,  or  "buccal  capsule,"  is  of  half-oval  or 
cup  shape,  the  anterior  axis  curved  and  long,  the  posterior 
shorter  and  nearly  straight.  The  bottom  of  the  mouth  cav- 
ity is  flat,  uneven,  and  nearly  transverse  to  the  long  axis  of 


ZOOLOGIC  FEATURES.  55 

the  animal.  (Fig.  3.)  Seen  from  the  front,  the  mouth 
is  somewhat  longer  dorso-ventrall}^  than  laterally.  The 
framework  of  the  mouth  is  made  up  of  a  number  of 
chitinous  plates,  or,  according  to  Looss,  a  continuous  plate 
with  suture-like  depressions,  giving  it  rigidity,  but  per- 
mitting changes  of  shape,  such  as  are  demanded  by  the 
function  of  the  mouth,  and  especially  holding  on  to  or  let- 
ting go  the  mucosa  of  the  host.  The  shape  of  the  opening 
varies  much  with  the  degree  of  dilatation  of  the  orifice  at 
the  time  of  examination  or  fixation.  On  the  ventral  side  of 
the  capsule,  just  within  the  cavity,  are  two  pairs  of  sharp- 
pointed,  curved,  hook-shaped  teeth;  at  the  base  of  the  cap- 
sule, on  the  ventral  side,  two  triangular  pointed  teeth,  or 
''lancets,"  and  on  the  front  of  the  dorsal  part  two  tooth-like 
structures  separated  by  a  fissure.  "Beneath  the  buccal 
rim  the  lining  of  the  cavity  is  thrown  into  six  papillary 
prominences,  characteristic  of  the  entire  group."  (Smith.) 
In  the  middle  of  the  dorsal  wall  of  the  mouth  capsule  is  the 
orifice  of  the  duct  of  the  dorsal  esophageal  gland.  From 
the  hook-shaped  ventral  teeth  the  so-called  cervical  glands 
extend  almost  to  the  middle  of  the  body.     (Fig.  8.) 

The  esophagus  begins  at  the  base  of  the  buccal  capsule, 
and  extends  as  a  thick-walled,  long  flask-shaped  organ,  700 
to  800  microns  long  and  150  to  175  microns  wide  at  the 
widest  (posterior)  part.  Its  lumen  on  transverse  section  is 
triangular  or  triradiate.  At  the  lower  end,  above  the  nar- 
rower intestine,  is  a  trilobed  valve.  Looss  says  the  muscles 
along  the  three  angles  of  the  esophagus  can  be  distinguished 
optically  and  chemically  from  the  ordinary  muscles  along 
the  lumen.  Between  the  esophagus  and  the  body  wall  are 
the  well-developed  nervous  system  and  the  esophageal 
glands.  The  former  appears  to  communicate  directly  with 
the  nervous  ring,  and  consists  of  three  longitudinal  nerves 
which  run  the  whole  length  of  the  esophagus  in  the  middle 
line  of  the  three  sectors.     At  three  places  are  annular  com- 


56  HOOKWORM  DISEASE. 

misural  fibers,  from  which  finer  fibers  pass  in  difi^erent 
directions. 

Lying  in  the  three  grooves  along  the  esophagus  are  three 
small  glands,  called  the  esophageal  glands  (Figs.  8,  9), 
which  become  continuous  toward  the  posterior  part  of  the 
esophagus.  Their  ducts  pass  forward  and  empty  into  the 
buccal  capsule.  According  to  Looss,  the  ducts  of  the 
lateral  glands  open  close  to  the  rim  of  the  mouth,  outside 
the  lateral  hook-shai^ed  teeth,  and  that  of  the  posterior 
gland  in  the  dorsal  wall  of  the  capsule.  Smith  is  not  able 
to  differentiate  the  cephalic  or  head  glands  of  Looss  from 
the  anterior  ends  of  the  esophageal  glands. 

Near  the  level  of  the  jDosterior  end  of  the  esophageal 
glands,  about  midway  in  the  length  of  the  esophagus,  or 
500  to  600  microns  from  the  front  of  the  head,  on  each  side, 
is  a  small  conical  papilla.  Through  this  opens  the  duct 
(sometimes  called  the  "excretory  canal")  of  the  cervical 
gland,  a  large  glandular  structure  lying  along  the  caudal 
end  of  the  esophagus  and  the  cephalic  end  of  the  intestine. 
(Figs.  8,  9.)  The  chyle-gut  is  made  up  of  two  rows  of  cells, 
surrounded  by  a  muscular  wall. 

On  each  side  of  the  anus  in  each  sex  are  several  small 
bodies  formerly  called  ganglion  cells  or  "anal  glands," 
which  open  into  the  intestinal  canal.  Their  function  is  un- 
known. 

The  sexual  opening  of  the  female  in  ankylostoma  duo- 
denale  is  at  the  posterior  third  of  the  body.  Mink  (1909) 
reported  an  anomaly  in  an  old  world  worm — the  vagina 
opening  at  the  junction  of  the  anterior  and  middle  thirds. 
The  short  vaginal  tube  passes  in  and  divides  into  an  an- 
terior and  posterior  uterus,  each  one  continuous  with  the 
narrow  ovary  which  lies  in  transverse  folds  along  the  in- 
testine. According  to  Looss  the  length  of  each  genital  tube 
is  five  to  six  times  the  length  of  the  body  of  the  worm,  the 


ZOOLOGIC  FEATURES.  57 

total  length  tlierefoi'e  being  ten  to  twelve  times  as  long. 
The  beginning  of  the  nterns  in  all  mature  females  contains 
masses  of  spermatozoa,  and  is  sometimes  called  the  "recep- 
tacnlum  seminis."  The  ovary  of  the  posterior  uterus  coils 
upon  itself  and  passes  forward,  to  terminate  with  the  an- 
terior ovary  in  the  anterior  half  of  the  body  of  the  worm. 
At  the  end  of  the  vagina  is  the  complicated  "ovijector," 
surrounded  by  a  dense  layer  of  muscle  cells.  Looss  gives 
the  two  parts  of  this  organ  the  names  ''pars  haustrix"  and 
''pars  ejectrix." 

Within  the  uteri  the  characteristic  ova  are  seen  in  great 
numbers,  and  in  varying  degrees  of  segmentation.  Smith 
speaks  of  some  with  embrj^os  in  the  uterus,  but  does  not  say 
whether  these  were  in  recently  passed  worms.  We  have 
never  seen  this,  and  think  it  probable  the  embryos  had  de- 
veloped after  the  worms  left  the  body  of  the  host  in  old 
specimens. 

The  male  sexual  glands  have  an  appearance  analogous 
to  that  of  the  female,  and  consist  of  a  long  plicated  tube 
along  the  intestine  on  each  side  of  the  worm,  reaching  as 
far  as  the  cervical  glands,  opening  into  a  sac,  the  seminal 
vesicle,  about  the  middle  of  the  body.  From  this  a  tube, 
the  ejaculatory  duct,  passes  to  the  cloaca,  which  opens  in  a 
papilla  on  the  ventral  side  of  the  tip  of  the  tail,  within  the 
bursa.  (Fig.  2.)  The  duct  is  covered  b}^  the  "cement 
gland,"  the  secretion  of  which  serves  to  fasten  the  male  to 
the  female  during  copulation.  The  opening  of  this  is 
guarded  by  a  chitinous  forked  process,  the  point  directed 
toward  the  tail,  and  the  intercornual  space  occupied  by  a 
delicate  valve-like  layer.  From  the  opening  two  long 
slender  "spicules"  (Fig.  2)  extend.  They  vary  in  length, 
but  are  almost  two  millimeters  long  generally.  Each  one 
has  at  its  base  an  "exsertor"  muscle  and  two  retractor 
muscles. 


58 


HOOKWORM  DISEASE. 


The  bursa  is  an  umbrella-like  expansion  of  cuticular 
folds,  supported  by  extensions  of  the  muscular  body  wall, 
spoken  of  as  rays.  The  dorsal  lobe  is  not  divided,  and  the 
dorsal  rays  are  united  to  about  two-thirds  of  their  length 


Tail 


Dorsal  ray 


Dorsolateral  ray 
Lateral  ray 


...,  Sutaventral 
ray 


Ventrolateral 
ray 


Ventral  ray 


Fig-.  4.  A,  caudal  bursa  and,,  tail  of  male  uncinaria  duodenalis.  B,  caudal 
bursa  and  tail  of  male  uncinaria  Americana.  Drawn  to  scale  to  show  differ- 
ence in  size.      (After  Allen  J.  Smith.) 

from  the  base.  Each  division  is  tripartite.  There  is  no 
ventral  lobe.  The  bursa  and  its  muscular  rays  enable  the 
male  in  sexual  contact  to  grasp  firmly  the  body  of  the 
female  and  properly  coapt  the  sexual  parts.     (Fig.  4.) 


S^ 


Fig'.  5.  Ankj'lostoma  duodenale 
in  copulation.  Drawn  by  Dr.  J.  H. 
Gage  from  specimen  presented  by 
Dr.  Walter  Brem. 


Fig.   6. 
from  dog. 


Copulating-  hoolvworms 


The  eggs  are  oval,  with  broadly  rounded  poles;  the  shell 
is  colorless,  measuring  0.056  to  0.061  millimeters  in  length 
and  0.034  to  0.038  millimeters  in  width.  (Fig.  11.)  In 
fresh  stools  the  eggs  are  usually  in  four  segments,  rarely  in 
fewer  or  more,  and  with  a  broad  space  between  the  seg- 
ments and  the  shells.     (See  Chapter  VII.) 


ZOOLOGIC  FEATURES. 


59 


Necator  Americanus. 

Synonyms. — Uncinaria  Americana — Stiles,  1902;  ankyl- 
ostoiiinm  Americanum — von  Linstow,  1903;  uncinaria 
(necator)  Americana — Stiles,  1903;  micinaria  liominis — 
AsMord,  King,  and  Gutierrez,  1904. 


Fig-.    7.     Necator    Americanus.     Upper    lialf    males,    lower    half    females. 
Inch  measure. 

The  name  (necator  =  murderer)  given  by  Stiles  to  the 
species  first  shown  by  him  to  have  generic  characters. 
Stiles  first  named  it  uncinaria  (1902),  having  clearly  de- 
scribed the  differences  between  uncinaria  cluodenalis,  but 
believing  the  worm  to  belong  to  the  same  genus.  It  is  in- 
teresting to  note  that  Lutz,  in  1888,  stated  that  the  Brazil- 
ian hookworm  did  not  have  hook-shaped  teeth.  Leuckart's 
description  of  dochmius  duodenalis   (1876)   was  based  on 


GO 


HOOKWOK^I  DISEASE. 


new  world  specimens.  Looss  suggests  tlie  latter  were  sent 
by  Wuclierer  or  Lutz  from  Brazil,  but  the  original  material 
could  not  be  found.  Allen  J.  Smith  also  recognized  the 
difference  between  this  and  the  old  world  species.  Both 
terms  of  the  name  have  been  criticised — ''necator"  because 
the  parasite  is  not  more  murderous  than  its  old  world  con- 
gener, and  ''Americanus"  because  it  has  a  world- wide  ex- 
tent. The  objections  are  invalid  from  the  standpoint  of 
zoologic  nomenclature. 

Buccal  cavity  Ventral  buccal  lip 

Border  of  membranous  mouthi, 

\-  Buccal  papillcB 


Dorsal  conical  tooth 


Head  g-land  (?) 


Esophageal  gland 


Dorsal  buccal  lip 


Esophagus 


Duct  of  cervical  gland  opening 
on  cervical  papilla 

Fig.  8.     Dorsal  aspect  of  head  end  of  uncinaria  Americana. 
J.  Smith.) 


(After  Allen 


This  worm  is  almost  as  long  as,  but  more  slender  than, 
ankylostoma.  The  males  measure  6  to  10  millimeters  and 
the  females  8  to  15  millimeters.  (Fig.  7.)  The  mouth 
capsule  is  small  and  glol)ular  and  its  orifice  rather  quad- 
rate.    (Fig.  10.)     There  are  no  teeth  on  the  free  edge,  but 


ZOOLOGIC  FEATURES. 


61 


two  broad  lips — dorsal  and  ventral — extend  inward  to  or 
beyond  the  edge  of  the  membranous  lip.  The  base  of  the 
larger  of  the  lips  reaches  from  the  ventromedian  line  to 


Ventral  lancets  Chitinous  buccal  capsule 


Head  glands  (?) 


Esophageal  gland 


Cervical  papil 


Cervical  gland 


Papillae 


uccal cavity 
Dorsal  conical  tooth 
Liateral  lancets 


[•Esophageal  gland 


Esophagus 


Intestine 


Fig.  9.     Lateral  aspect  of  head  end  of  uncinaria  Americana.      (After  Allen 
J.  Smith.) 

about  the  middle  of  the  lateral  aspect  of  the  rim;  the 
smaller  one  from  the  dorsomedian  line  about  two-thirds  of 
the  distance  to  the  ventral  lip.  They  cover  two  cutting- 
plates.     (Figs.    8,    9.)     There    are    two    pairs    of    ventral 


62 


HOOKWORM  DISEASE. 


teetli — tlie  lower  pair  small  and  conical,  and  a  blunt,  coni- 
cal, dorsal  tooth  (Fig.  8),  projecting  into  the  capsule. 
Through  it  passes  the  duct  of  the  dorsal  esophageal  gland. 
Near  its  base,  on  each  side,  is  a  chitinous  plate. 


Buccal  hook 
Buccal  teet 


Anterior  buccal  lip 

Posterior  buccal  lip 
iDorsal conical  tooth 


A  B 

Fig.  10.  A,  dorsal  view  of  liead  end  of  uncinaria  duodenalis.  B,  dorsal 
view  of  head  end  of  uncinaria  Americana.  Drawn  to  scale  to  show  difference 
in  size.      (After  Allen  J.  Smith.) 

The  sides  of  the  bursa  are  very  long,  so  that  the  bursa 
seems  as  if  two-lobed.  (Fig.  4.)  The  female  genital  open- 
ing is  in  front  of  the  middle  of  the  body.  The  eggs  re- 
semble those  of  the  old  world  hookworm  closely,  but  are 


Fig-.  11.  Embryology  of  the  old  world  hookworm  (ankylostoma  duode- 
nale)  of  man;  a,  h,  c,  d,  e,  f,  g,  segmentation  of  the  eg-g-;  h,  i,  j,  the  embryo;  fc, 
a  rhabditiform  embryo  escaping  from  its  eggshell;  /,  m,  empty  eggshells. 
Greatly  enlarged.      (After  Perroncito.) 


ZOOLOGIC  FEATURES.  63 

sligiitly  larger  (0.054  to  0.072  millimeters  long  and  0.036 
millimeters  tliick),  and  tapering  toward  the  poles.  (Fig. 
13.) 

The  vital  characteristics  of  necator  Americanus  have  not 
been  so  closel}^  investigated  as  those  of  ankylostoma,  but 
are  the  same  so  far  as  examined.  Experiments  by  Claude 
A.  Smith  and  Fieri  (though  the  latter  rejected  the  con- 
clusions) prove  the  skin  infection  to  take  place  in  the  same 
way. 

Ankylostoma  and  necator  have  been  found  only  in  human 
beings.  Von  Linstow  (1903)  reported  the  occurrence  of 
necator  in  a  chimpanzee  (simia  troglodytes)  in  West  Africa, 
but  Looss  doubts  the  diagnosis. 

Development  of  Ankylostoma  Duodenale. 

The  females  lay  their  eggs  in  the  intestine  of  the  host, 
and  the  ova  are  expelled  with  the  feces,  and  under  proper 
conditions  develop.  The  rapidity  of  development  depends 
upon  the  temperature,  moisture,  and  available  oxygen,  as 
also  perhaps  on  absence  of  light.  Development  is  most 
rapid  at  25°— 35°  C.  (77°— 95°  F.).  A  few  develop  at 
22°  C.  (71°  F.),  and  Tenholt  found  that  some  developed  in 
mines  at  20°  C.  (68°  F.)  from  eggs  to  larvse  in  fourteen  days. 
Freezing  often  kills  ova,  and  low  temperature  prevents  seg- 
mentation, but  the  possibilities  of  the  development  of  these 
worms  appear  very  strikingly  from  some  experiments  of 
Oliver  (1910).  He  froze  feces  until  hard,  but  after  gentle 
thawing  larvae  appeared  on  the  sixth  day.  Kept  in  a  cold 
cellar  at  15°— 17°  C.  (59°— 62.3°  F.)  for  ten  weeks,  there  was 
no  segmentation,  but  when  raised  to  a  moderate  tempera- 
ture segmentation  went  on  and  gave  rise  to  stronger  and 
more  vigorous  larvji?  than  those  hatched  immediately.  Ex- 
posure to  light  snow  does  not  kill  eggs  or  larvae.     Tempera- 


64 


HOOKWOEM  DISEASE. 


tures  of  50°  C.  (122°  F.)  kill  larvae,  probably  from  drying. 
Complete  desiccation  is  one  of  the  most  certain  causes  of 
death.     Deprivation  of  oxygen   also   checks   development, 


Fig.  12.  Two  larvfp  of  the  old  world  hookworm  at  the  end  of  the  second 
stage  ("encysted  larv.-E").  representing  the  young  worms  retracted  from  their 
skin.      (After  Perroncito. > 

and,  if  continued  sixteen  days,  the  eggs  die.  It  is  the  pres- 
ence of  oxygen  that  makes  eggs  on  the  surface  of  stools 
develop  more  rapidly  than  those  in  the  depths,  which  either 


ZOOLOGIC  FEATURES.  65 

die  or  develop  only  when  the  mass  becomes  loose.  (See 
Chapter  V.)  Direct  sunlight  lulls  the  ova,  diffuse  day- 
light checks  development,  and  darkness  favors  it. 

The  eggs  resist  adverse  conditions  very  much  at  times. 
Lambinet  and  Boycott  and  Haldane  found  they  could  be 
kept  from  air  nine  to  ten  days  and  then  develop. 


Fig.   13.     Ova  of   (A)   uncinaria  duodenalis  and    (B)    uncinaria  Americana. 
Drawn  to  scale  to  show  comparative  size.      (After  Allen  J.  Smith.) 

Eggs  also  die  usually  in  water  or  in  watery  stools,  but,  on 
the  other  hand,  larvae  can  often  be  cultivated  under  such 
conditions.  Larva  can  be  raised  sometimes  either  in  the 
natural  stool  or  one  made  into  a  thick  paste  with  water, 
but,  as  Looss  pointed  out,  acid  fermentation  of  stools  may 
kill  all  the  larvae,  even  before  they  escape  from  the  egg- 
shells. Boycott  and  Haldane,  however,  found  that  larvae 
grew  for  them  in  acid  stools.  Looss  also  points  out  that 
the  constituents  of  the  feces  are  important  in  this  con- 
nection. In  his  own  infection  (experimentally  produced) 
he  found  that  pure  vegetable  diet  produced  a  less  favorable 
medium  for  the  ova  than  mixed  diet,  especially  if  stools 
from  the  latter  were  mixed  with  equal  part  of  moderately 
finely  pulverized  animal  charcoal  (made  from  bones,  not 
blood)  and  made  into  a  thick,  tenacious  mass  with  water. 
Diarrheal  stools  mixed  with  animal  charcoal  also  permit  all 
the  ova  to  develop. 

While  complete  desiccation  kills  both  eggs  and  larvae,  en- 
cysted larvae  resist  drying  for  a  long  time.  There  is 
much  divergence  in  regard  to  the  effect  of  drying  on  ankyl- 
ostoma  larv<T,  but  the  differences  of  opinion  probably  de- 


66  HOOKWORM  DISEASE. 

pend  upon  errors  in  teclinic — sometimes  perhaps  on  mis- 
takes in  the  diagnosis  of  the  larvae. 

The  larvae,  after  escaping  from  the  eggs,  feed  on  the  feces 
and  grow.  They  measure  0.2  to  0.25  millimeters  long  and 
0.01  to  0.017  millimeters  thick.  They  are  at  first  rhabditi- 
form — thaf  is,  the  esophagus  shows  three  parts.  It  be- 
comes narrow  beyond  the  middle,  and  then  swells  out  again 
in  an  onion  shape.  In  the  interior  of  the  swelling  are  three 
small  valves,  that  can  sometimes  be  seen  to  open  and  shut. 
(Fig.  11,  k.)  Characteristic  of  the  hookworm  larva  is  a 
long,  cylindrical  mouth  cavity,  with  a  globular  dilatation  at 
the  posterior  part,  lined  by  a  highly  refracting  membrane. 
The  tail  end  is  sharply  pointed;  in  front  of  it  is  the  anus, 
and  still  farther  in  front  the  anlage  of  the  sexual  organs, 
showing  as  a  small  oval  body. 

Four  moults  are  passed  through  during  development  of 
the  larvae,  making  five  stages  after  incubation,  including 
full  development.  The  first  shedding  of  the  skin,  or 
ecdysis,  takes  place  usually  within  two  to  five  days  after 
incubation,  depending  upon  the  temperature  and  other  con- 
ditions. In  this  there  is  no  change  of  shape.  The  new  skin 
is  formed  under  the  old  one.  After  this  moult,  again  with  a 
lapse  of  time  depending  on  the  temperature,  the  larvae  grow 
and  change  their  shape.  The  body  becomes  longer  (0.7  to 
0.8  millimeters)  and  thinner,  and  the  characteristic  shape  of 
the  mouth  and  esophagus  are  lost.  The  second  ecdysis  is 
prepared  for,  and  reached  in  five  to  nine  days  usually,  but 
the  old  skin  is  not  shed  as  soon  as  the  new  one  is  ready.  On 
the  contrary,  the  old  skin  surrounds  the  body  as  a  delicate 
sheath,  in  which  the  larva  has  room  to  move  forward  and 
back.  This  is  the  (falsely)  so-called  "encysted"  stage. 
(Fig.  12.)  The  larvae  are  now  called  "ripe."  Growth 
and  feeding  cease,  and  the  free  stage  of  the  larvae  is  ended. 
They  now  endeavor  to  leave  the  feces  and  to  get  into  moist 


ZOOLOGIC  FEATURES.  67 

earth,  moist  wood,  or  water.  As  Looss  discovered  and  re- 
ported in  1897,  tliey  bore  through  filter  paper  on  which 
feces  are  incubating,  and  in  that  way  can  be  easily  obtained 
free  from  fecal  contamination.  They  also  pass  through  a 
sand  filter,  even  if  the  water  is  not  running.  In  various 
media  they  may  live  a  long  time,  and  show  remarkable  te- 
nacity of  life.  Belger  and  Oliver  found  them  alive  in  water 
sealed  in  vaseline  four  months.  One  of  them  wriggled  into 
the  vaseline  and  lived  nearly  to  the  end  of  the  fifth  month. 
Looss  kept  them  alive  in  water  three  hundred  days,  and 
Oliver  more  than  eleven  months.  Perner  found  them  alive 
in  mine  sludge  ten  months  after  the  mine  had  been  closed. 
In  distilled  water  they  live  only  two  to  nine  days.  During 
this  time  they  live  upon  certain  granular  particles  in  the 
glands  of  the  intestine,  the  latter  becoming  in  time  almost 
transparent,  instead  of  granular  and  opaque  as  before.  In 
water  they  are  not  able  to  move  freely,  but  sink  if  the  water 
is  still.  On  the  other  hand,  if  the  temperature  is  not  too  low, 
they  have  a  strong  tendency  to  migrate,  and  especially  to 
crawl  up  on  all  sorts  of  objects  kept  moist  by  water.  Looss 
found  that  if  he  put  a  piece  of  wood  in  the  culture  glass, 
with  one  end  out  of  the  water,  all  the  larvae  in  a  short  time 
would  crawl  up  to  the  top  of  the  stick,  which  was  kept  moist 
by  the  water  below.  Tenholt  reports  an  observation  in 
which  larvae  that  developed  from  ova  in  feces  at  the  lower 
end  of  a  wet  mine  timber  reached  a  height  of  one  meter 
above  the  ground  in  twenty  days,  or  not  more  than  sixteen 
days  after  reaching  the  larval  stage.  The  same  observer 
found  larvae  in  the  cracks  between  the  boards  of  a  bath- 
house. Hermann  and  Galli-Valerio  observed  penetration 
of  elder  pith  by  larvae  over  night.  It  is  in  this  stage  that 
the  larvae  are  infectious.  Eggs  or  young  larvae  are  not  cap- 
able of  infection,  even  if  swallowed. 

Leichtenstern  formerly  believed  that  ankylostoma  could 


68  HOOKWOEII  DISEASE. 

develop  by  lieterogeny — that  is,  the  larvae  developed  out- 
side the  body  into  males  and  females,  the  offspring  of  which 
in  turn  were  infectious.  Leichtenstern  later  abandoned  the 
view,  but  it  was  put  forward  also  by  Giles  in  Assam,  and 
later  bys  Ozzard,  Annett,  and  Eoss.  As  has  been  pointed 
out  by  Looss  and  other  observers,  and  recently  (1909)  by 
Leiper  in  criticism  of  Ozzard,  the  idea  depends  upon  con- 
fusion of  ankylostoma  larvae  with  those  of  other  nematodes, 
especially  strongyloides  stercorals,  sometimes  free  living 
nematodes,  of  which  there  are  so  many  species,  and  failure 
to  sterilize  the  sand  used  for  culture  medium. 

As  an  example  of  the  necessity  of  extreme  care  in  such 
work,  Leiper  cites  an  observation  in  which  a  stool  was  kept 
in  a  glass  bottle  in  the  laboratory  for  a  year.  The  bottle 
had  formerly  contained  an  alcohol  preparation.  Later  the 
bottle  was  found  to  contain  forms  resembling  free  adult 
strongyloides  intestinalis,  but  it  became  certain  later  that 
they  were  the  larvae  of  free  living  nematodes.  Leiper  also 
points  out  that,  while  the  ova  of  hookworms  as  found  in 
human  feces  are  diagnostic,  they  can  not  be  distinguished 
from  the  larvae  of  all  other  nematodes. 

As  Looss  has  shown,  the  picture  of  Giles,  purporting  to 
represent  the  development  of  the  male  rhabditis  of  ankyl- 
ostoma, shows  three  different  species,  as  indicated  by  the 
shape  of  the  tails. 

The  larvae,  like  the  eggs,  are  easily  killed  by  drying. 
Galli-Valerio  and  also  Fieri,  however,  found  that  they  could 
be  dried,  but  revived  up  to  twenty-four  hours  after.  Differ- 
ences in  the  results  of  various  experimenters  are  to  be  ex- 
plained by  the  difficulty  of  perfect  desiccation  within  the 
capsule.  Galli-Valerio  found  that,  while  noncapsulated 
larvae  die  at  40°  C,  encapsulated  ones  could  resist  a  temper- 
ature of  almost  50°  C.  He  also  found  encapsulated  larvre 
alive  in  a  bottle  of  feces  kept  nearly  a  year.  The  feces 
were  still  moist,  and  the  larvae  only  on  the  surface. 


ZOOLOGIC  FEATURES.  69 

Chemical  disinfectants. — The  larvae  are  resistant  to  chem- 
ical agents.  Scliiift'ner  kept  them  alive  almost  four  months 
in  water  witli  two  or  three  drops  of  1-percent  quinine  solu- 
tion to  10  cubic  centimeters.  Oliver  found  that  sea- water 
killed  them  in  tliirty-seven  minutes. 

Stronger  disinfectants  kill  both  eggs  and  larvae,  as  is 
mentioned  more  fully  in  Chapter  IX. 

An  interesting  light  was  thrown  on  the  possible  modes  of 
dissemination  of  the  eggs  and  larvse  of  hookworms  by  Galli- 
Valerio  (3905).  He  placed  eggs  and  larvse  of  ankylostoma 
duodenal e  in  a  bottle  with  flies,  and  on  washing  the  flies 
found  many  eggs  and  encapsulated  larvse  which  had  ad- 
hered to  their  bodies,  but  none  in  the  flies'  intestines. 

Having  been  taken  into  the  body  in  any  of  the  various 
ways  described  in  Chapter  IV,  the  larvae  undergo  two  other 
moults  before  becoming  mature.  The  details  of  these 
stages  are  not  known,  but  certain  facts  are  established. 
Both  in  the  mouth  infection  and  in  some  cases  of  skin  infec- 
tion, as  in  Looss'  experiments  on  young  dogs,  the  larvae 
appear  in  the  intestine  in  ten  days. 

In  skin  infection  in  guinea  pigs,  larvae  reach  the  trachea 
in  fourteen  days.  They  have  not  grown  appreciably,  but 
are  perfectly  agile.  They  evidently  do  not  all  travel  with 
the  same  speed.  Doubtless  many  are  kept  back  for  a  time 
or  permanently  by  the  lymph  glands.  Looss,  however, 
found  eggs  in  the  feces  after  skin  infection  in  thirty  to 
thirty-five  da^^s.  Tenholt's  assistant  found  a  few  eggs  in 
his  stools  forty-seven  days  after  skin  infection,  and  then 
they  rapidly  became  more  numerous.  In  the  accidental  in- 
fection in  himself  Looss  did  not  find  eggs  until  the  seventy- 
first  day,  the  same  period  that  elapsed  in  Fieri 's  case,  but 
in  young  dogs  Looss  found  a  few  adult  worms  at  thirty  to 
thirty-five  days. 


CHAPTER  IV. 

^  MODES  OF  INFECTION. 

Two  modes  of  infection  with  hookworms  are  known  and 
have  been  proved  experimentally — i.  e.,  through  the  mouth 
directly  and  through  the  mouth  indirectly  by  way  of  the 
skin.  For  reasons  that  will  appear  below,  direct  mouth 
infection,  though  it  may  occasionally  occur,  is  of  minor  im- 
portance in  the  production  of  hookworm  disease.  Skin  in 
fection,  we  believe,  is  practically  the  only  source  of  the 
disease.  Different  species  of  hookworms  have  been  found 
parasitic  in  various  lower  animals — namely,  dogs,  sheep, 
cattle,  horses,  pigs,  cats,  foxes,  seals,  badgers,  etc.  These 
are  distinct  from  those  infecting  man,  and  have  not 
been  found  in  man.  Two  species  infect  man — ankylostoma 
duodenale  and  uncinaria  Americana — ^both  of  which  have 
been  found  experimentally  to  be  capable  of  entering  the 
skin  of  lower  animals,  but  they  have  not  reached  adult 
life  in  the  intestinal  canal  of  any  animal  besides  man, 
except  possibly  the  chimpanzee,  the  gibbon,  and  the  gorilla. 
They  reach  adult  life  or  the  reproductive  stage  only  in  the 
intestinal  canal  of  man,  where  they  lay  eggs,  which  pass 
out  with  the  feces.  The  eggs  can  not  hatch  in  the  intestinal 
canal  for  lack  of  oxygen  and  possibly  for  other  reasons, 
such  as  the  presence  of  acids,  gases,  etc.,  produced  by  the 
intestinal  bacterial  flora.  Moreover,  it  has  been  shown  con- 
clusively by  Looss,  working  with  the  old  world  hookworm, 
by  Claude  A.  Smith,  working  with  the  American  species, 
and  by  others,  that  the  young  worms  can  not  infect  until 
they  have  reached  a  certain  stage  (the  encysted  stage)  of 
their  life,  which  requires  at  least  four  or  five  days  after  they 

70 


MODES  OF  INFECTION.  71 

are  hatched  out,  which  itself  requires  eighteen  hours  or 
more  after  the  feces  have  been  expelled.  The  above  stated 
facts — that  the  reproductive  stage  of  the  parasite  is  reached 
only  in  the  intestinal  canal,  that  the  species  infecting  man 
do  not  infect  other  animals,  that  the  eggs  do  not  hatch  in 
the  intestinal  canal,  and  that  the  larvse  are  not  infectious 
until  they  are  at  least  four  or  five  days  old — show  that  the 
feces  of  infected  persons  are  the  real  sources  of  every  hook- 
worm infection,  and,  further,  that  a  man  can  not  directly 
infect  himself. 

The  number  of  eggs  passed  with  each  stool  of  a  heavily 
infected  person  is  enormous.  Leichtenstern  estimated  the 
number  passed  daily  in  one  of  his  cases  of  ankylostomiasis 
to  be  over  4,000,000.  Bass  counted  the  eggs  in  one  deci- 
gram of  feces  from  a  severe  case  of  uncinaria  Americana  in- 
fection, originating  in  Louisiana,  and  calculated  the  num- 
ber in  the  entire  stool  to  be  4,490,000.  We  estimated  that 
the  daily  stool  of  a  patient  with  apparently  only  a  moder- 
ate infection,  and  70  percent  of  hemoglobin,  contained 
1,700,000  eggs.  Remembering  that  the  average  number  of 
worms  in  the  severe  cases  in  this  country  ranges  between 
1,000  and  4,000,  it  is  obvious  that  it  would  not  require  more 
than  one-thousandth  part  of  the  eggs  in  one  such  stool 
to  give  rise  to  a  severe  infection  if  all  developed.  In  the 
light  of  these  figures,  the  wonder  is  that  the  disease  is  not 
far  more  destructive  of  human  life  than  it  is. 


Requirements  for  Hatching. 

Hookworm  eggs  do  not  hatch  in  the  intestinal  canal,  as 
has  already  been  stated,  nor  do  they  hatch  in  undiluted 
feces,  except  under  certain  special  conditions.  We  have 
often  kept  feces  containing  hookworm  eggs  in  the  labora- 
tory for  months  at  a  time  in  liquid  condition  without  any 


/2  hookworjm  disease. 

hatching-  whatever.  In  fact,  we  have  kept  them  in  this 
condition  in  tlie  bacteriologic  incubator  at  body  tempera- 
ture for  a  month  and  have  never  seen  hatching  occur  in  such 
specimens.  If,  on  the  other  hand,  pure  feces  are  exposed  to 
drying,  maay  of  the  eggs  near  the  partially  dried  out  sur- 
face of  the  fecal  mass  will  hatch  out,  but  the  eggs  deeper  in 
remain  undeveloped.  Claude  A.  Smith  noted  that  if  feces 
containing  uncinaria  eggs  were  exposed  to  flies  that  infect 
them  with  their  larvae,  the  constant  mixing  and  aeration 
(oxygenation)  by  the  larvae  crawling  through  the  mass  per- 
mits rapid  and  complete  hatching.  We  have  had  occasion 
to  confirm  this  observation  in  several  instances.  Though 
hatching  in  undiluted  feces  may  occur  under  the  favorable 
circumstances  mentioned,  the  larvae  die  out  before  they  are 
twenty-four  to  forty-eight  hours  old  and  before  they  are  in- 
fectious, except  that  a  few  may  sometimes  live  longer  in  the 
partially  dried  out  feces.  Dilution  of  the  feces  with  one  or 
more  times  their  bulk  of  almost  any  inert  porous  substance 
— like  charcoal,  sand,  dirt,  etc. — puts  them  in  the  most  fav- 
orable condition.  The  best  results  we  have  ever  seen  were 
obtained  with  equal  quantities  of  charcoal  and  feces. 
Looss  found  animal  charcoal  the  most  satisfactory  diluent. 
We  have  seen  nearly  as  good  results  from  using  sand.  We 
made  the  following  experiments  for  the  present  work: 

Feces  containing  many  uncinaria  eggs  were  mixed  with 
each  of  the  following  materials  about  in  the  proportion  of 
one  part  feces  to  two  of  diluting  material:  powdered  char- 
coal (pine),  white  sand,  sand  plus  about  5  percent  slacked 
lime,  sandy  soil,  black  clay  soil,  and  pipe  clay,  all  sterilized 
before  mixing.  All  were  thoroughly  mixed  and  contained 
about  the  same  amount  of  moisture.  An  accident  occurred 
to  the  specimen  which  the  limed  sand  entered  into  and  it 
was  lost.  The  remaining  five  specimens  were  placed  in 
glass  dishes  without  covers  and  put  in  a  bacteriologic  in- 


MODES  OF  INFECTION.  73 

ciibator  (at  37°  C),  in  which  several  sponges  saturated  with 
water  were  placed  to  keep  up  moisture  and  prevent  undue 
drying  out  of  the  specimens.  After  fifty-four  hours  in  the 
incubator  the  cultures  were  carefully  examined  and  the 
following  results  noted : 

Feces  plus  charcoal:  many  larvai',  a  few  empty  shells,  and 
no  eggs  found. 

Feces  plus  sand:  many  larvae,  a  few  shells,  and  two  seg- 
menting eggs  found. 

Feces  plus  sandy  soil:  many  larvae,  a  few  segmenting 
eggs,  and  three  containing  embryos  were  found. 

Feces  plus  black  clay  soil:  in  slides  made  from  near  the 
surface  a  very  few  larvae  were  found  and  many  more  eggs, 
many  of  which  contained  dead  embryos.  Deep  in  the  mix- 
ture no  progress  toward  hatching  appeared  to  have  been 
made. 

Feces  plus  pipe  clay:  no  larvae  could  be  found,  but  near 
the  surface  of  the  mixture  a  few  dead  embryos  could  be  seen 
in  the  egg  shells. 

The  charcoal,  sand,  and  sandy  soil  specimens  remained 
porous  and  friable,  but  the  clay  soil  and  pipe  clay  speci- 
mens ran  together  and  were  sticky.  In  spite  of  the  pre- 
caution to  prevent  it,  all  of  them  dried  out  considerably,  and 
the  clay  specimens  were  coated  with  a  thin  hard  crust.  The 
experiment  shows  that  best  hatching  follows  dilution  of 
feces  with  material  producing  a  porous  mixture,  whereas 
the  sticky  nonporous  mixture  prevents  hatching,  chiefly,  no 
doubt,  by  depriving  the  eggs  of  oxygen.  Where  the  soil  is 
sandy  and  porous,  rains  dilute  and  mix  feces  with  the  soil 
and  put  the  eggs  in  the  most  favorable  condition  in  this 
regard  for  hatching.  There  would  be  far  less  mixing  of 
feces  with  a  sticky  clay  soil,  and,  if  so  mixed,  hatching  is 
prevented.  This  may  explain  the  much  greater  prevalence 
of  the  disease  is  sandy  regions. 


74  HOOKWOEM  DISEASE. 

Moisture  is  very  necessary  for  hatching  of  hookworms, 
but  no  great  amount  is  required.  It  is  more  essential  for 
the  maintenance  of  the  life  of  the  larvae.  They  live  well  in 
water  or  moist  earth,  but  drying  soon  kills  them.  Bentley 
found  th^t  gentle  drying  for  six  hours  kills  them.  Rains 
are  important  in  scattering  the  feces  and  mixing  them  with 
the  soil,  and  also  in  keeping  up  the  essential  moisture. 
They  are  also  important  factors  in  producing  skin  infection 
by  liquefying  and  helping  to  apply  the  infectious  cultures 
to  the  skin,  as  we  shall  see  later. 

Shade  is  an  important  factor,  both  in  the  hatching  of 
hookworm  eggs  and  keeping  the  larvse  alive,  by  maintain- 
ing the  essential  moisture  and  preventing  fatal  drjdng. 
We  exposed  a  culture  of  six-day  old  uncinaria  larvse  to  the 
direct  April  sunshine  for  two  days,  adding  water  as  needed 
to  prevent  drying,  and  they  were  still  alive  and  active  at 
the  end  of  the  experiment. 

If  feces  containing  eggs  are  diluted  with  dirt,  sand, 
or  other  material,  and  favorable  conditions  of  moisture, 
warmth  (temperature  between  22°  and  35°  C.  =  71.6°  and 
95°  F.),  and  shade  exist,  the  microscopic  larvae  begin  to 
hatch  out  and  crawl  about  in  the  diluted  feces  iu  twenty- 
four  hours.  In  two  or  three  days  they  shed  their  skins. 
This  is  the  first  ecdysis.  After  about  five  days  from  the 
time  they  were  hatched  out  the  organism  begins  a  second 
stage  of  development  or  ecdysis,  but  this  time  it  remains  in- 
side of  the  skin  it  has  cast  or  retracted  from,  and  is  spoken 
of  as  encysted.  In  this  condition  it  is  capable  of  infecting, 
but  was  not  before.  Before  the  larva?  become  encysted  they 
are  easily  killed  by  sunlight,  changes  of  temperature,  too 
much  dilution  of  the  feces  with  water  (1  to  1,000  or  above), 
drying,  and  often  the  chemical  constituents  of  feces.  It 
results,  therefore,  that  actually  very  few  larvse  that  hatch 
out  reach  the  encysted  or  infectious  stage.     Only  in  rainy 


MODES  OF  IXFECTIOX.  75 

seasons,  or  wet  spells  lasting  six  or  more  days,  would  suf- 
ficient moisture  be  continually  supplied,  except  in  some 
specially  favorable  spots,  to  bring  them  to  this  stage.  Too 
much  rain  often  results  in  sufficient  dilution  to  kill  them. 
Only  in  favorable  places  or  favorable  seasons  do  they  es- 
cape the  destructive  sun's  rays  and  drying.  Only  in  warm 
seasons  do  they  hatch  out.  From  these  facts  result  the 
very  much  greater  jDrevalence  and  intensit}^  of  the  infection 
in  tropical  countries. 

In  the  encysted  condition  the  microscopic  larvas  may  live 
many  months  under  favorable  conditions  of  moisture,  shade, 
and  temperature.  They  resist  wonderfully  well  unfavor- 
able conditions  and  such  agents  as  chemicals,  but  are  killed 
by  strong  solutions  of  salt,  as  pointed  out  in  Chapter  III. 
They  live  well  in  shallow  water  or  moist  earth,  in  which 
they  come  near  the  surface  or  go  deeper  with  the  rise 
and  fall  of  moisture. 

Drinking  Water. 

Drinking  water  may  become  a  source  of  infection,  but 
the  probabilities  of  getting  any  considerable  number  of 
larvfB  in  this  way  seem  pretty  remote  on  account  of  the 
amount  of  contamination  that  would  be  required  (less  than 
one  part  feces  to  one  thousand)  to  maintain  the  life  of  the 
larvae  until  they  reach  the  encysted  stage,  and  especially  in 
view  of  the  fact  that  the  larvse  soon  sink  in  water.  Water 
containing  larvae  would  have  to  be  stirred  up  just  before  it 
is  drunk  to  become  a  source  of  infection.  Kef  erring  to  this, 
Stiles  remarks  that,  ''granted  that  they  do  sink  in  water,  a 
water  bucket  in  a  well  also  sinks,  and  the  water  from  sur- 
face wells  frequently  contains  sand  particles  that  are 
heavier  and  larger  than  uncinaria  larvae;  hence  we  can  not 
altogether  ignore  drinking  water  as  a  source  of  infection." 
Leichtenstern  showed  that  infection  by  mouth  can  occur  by 


76  HOOIvWORM  DISEASE. 

administeriiig  per  os  capsules  containing  the  larvae.  In 
about  six  weeks  ova  of  the  parasites  appeared  in  the  feces 
of  the  patient.  These  experiments  with  ankylostoma  have 
been  repeated  and  confirmed  with  nncinaria  Americana  by 
Claude  A.  Smith  and  others  in  this  country. 

Food. 

Food  that  has  been  contaminated  with  infected  mud  or 
water,  or  that  has  been  handled  with  dirty,  infected  hands, 
may  become  a  source  of  infection.  Smith  noted  the  habit 
the  encysted  larv«  have  of  crawling  up  along  the  sides  and 
cover  of  a  culture  dish,  which  suggests  another  way  in 
which  certain  food  may  become  infected.  Larvae  may 
crawl  up  on  the  leaves,  stalk,  or  fruit  of  such  vegetables  as 
lettuce,  celery,  strawberries,  water  cress,  etc.,  that  are  eaten 
raw,  and  they  may  be  swallowed  when  these  are  eaten.  No 
ordinary  washing  could  be  expected  to  remove  all  of  the 
larvae.  The  frequent  practice  of  defecating  in  the  barn- 
yard, where  the  feces  would  be  mixed  with  the  barnj^ard 
manure  and  frequently  used  to  fertilize  the  vegetable  and 
other  crops,  may  possibh^  be  a  source  of  infection.  In  the 
country  the  vegetable  garden  is  usualh"  located  behind  and 
near  the  house,  and  is  one  of  the  common  places  for  the 
location  of  the  privy,  if  one  is  provided.  It  serves  also  a 
frequent  place  for  defecation  of  the  women  and  children 
when  no  privy  is  used.  This  may  not  rareh^  be  a  source  of 
the  larvae  getting  on  vegetables,  and  thus  infecting  those 
who  eat  them  raw. 

Infection  Through  the  Skin. 

Looss,  in  1898,  while  experimenting  with  cultures  of 
ankylostoma  larvae,  found  that  getting  the  culture  on  his 
hands  produced  a  dermatitis.     Later  on,  finding  ova  in  his 


MODES  OF  INFECTION. 


77 


feces,  he  concluded  that  he  had  been  infected  through  the 
skin.  In  1903  he  proved  the  correctness  of  his  theory  by 
experiments.     Grassi,  Fieri,  and  Noe  dropped  water  con- 


Fiff  14  Experimental  hookworm  infection.  Tlie  soil  containing  the 
larvae  as  it  appeared  on  the  wrist,  the  tendons  and  veins  of  the  hand  showing- 
distinctly.      (Photograph  furnished  by  Dr.   Claude  A.   Smith.) 

taining  ankylostoma  larvae  on  their  own  arms.  In  the 
feces  of  only  one  of  them  were  ova  found  at  the  end  of  ten 
weeks.     They,  therefore,  concluded  that  Looss'  theory  of 


cwi,iA.s^;A,K 


Fig  15.  Experimental  hookworm  infection.  Shows  swelling  ot  wrist  and 
tendonl  of  hand,  and  vesicle  formation.  Second  day.  (Photograph  furnished 
by  Dr.  Claude  A.  Smith.) 

skin  infection,  deduced  from  his  experiments,  was  not  con- 
firmed, and  that  their  case  and  Looss'  were  instances  of 
accidental  mouth  infection. 


78 


HOOKWORM  DISEASE. 


Looss  then  repeated  his  experiments,  and  established  be- 
yond all  doubt  that  the  larvae  enter  the  skin  and  finally 
reach  the  intestine,  where  they  develop  to  adult  life.  He 
placed  some  drops  of  heavily  infected  water  on  the  arm  of 
a  man  whose  feces  showed  that  he  was  not  infected  up  to 
that  time.  'The  characteristic  dermatitis  soon  developed. 
The  next  day  the  arm  was  swollen,  in  a  week  the  swelling- 
subsided,  and  in  seventy-one  days  ova  were  found  in  the 
patient's  feces.     He  also   shaved  the  back  of  a  dog  and 


Fig.  16  Experimental  hookworm  infection.  Shows  the  large  crust  form- 
ing over  the  area  and  the  further  decrease  of  the  swelling.  (Photograph 
furnished  by  Dr.  Claude  A.  Smith.) 

placed  on  it  some  mud  heavily  infected  with  uncinaria 
caninum.  The  animal  was  properly  bandaged  to  prevent 
mouth  infection,  and  after  two  hours  the  mud  was  removed 
and  the  area  thoroughly  scrubbed  with  absolute  alcohol. 
The  mud  contained  only  one-sixth  as  many  larvae  as  it  did 
when  applied  to  the  dog's  skin.  The  dog  died  in  ten  days, 
and  at  autopsy  an  enormous  number  of  larvae  were  found 
on  and  in  the  walls  of  the  small  intestine.  He  infected  two 
other  puppies,  one  l)y  feeding  infected  milk  and  the  other 
by  applying  the  infectious  material  to  the  skin.     They  both 


MODES  OF  INFECTION. 


79 


died  in  a  few  days,  and  their  small  intestines  contained 
enormous  numbers  of  young  larva?.  These  experiments 
were  confirmed  by  Schaudinn,  Lambinet,  Hermann,  Cal- 
mette,  Tenholt,  and  Schiiffner. 

In  1902  Bentley  found  in  a  "water  sore,"  called  in  this 
country  ''ground  itch,"  "dew  poison,"  or  "toe  itch,"  a 
young  worm  which  he  thought  to  be  ankylostoma  duo- 
denale.  He  then  made  the  following  experiment:  A  cul- 
ture of  sterilized  soil  plus  feces  containing  ova  was  made, 
and  another  one  containing  no  ova;  both  were  properly  in- 


Fig:.  17.  Experimental  hookworm  infection.  Shows  confluent  vesicle 
formation,  with  slight  decrease  of  swelling-.  (Photograph  furnished  by  Dr. 
Claude  A.  Smith.) 


cubated  at  ordinary  room  temperature.  A  part  of  each  was 
gently  dried  for  eight  hours.  Six  hours'  drying  had  previ- 
ously been  found  sufficient  to  kill  the  larvae.  After  remois- 
tening  the  specimens  that  had  been  dried,  samples  of  the 
four  specimens  were  applied  to  the  wrists  of  the  subjects  of 
experiment  for  eight  hours,  and  then  they  were  removed. 
Within  fifteen  hours  after  the  application,  erythema  and  a 
papular  eruption  appeared  over  the  spot  where  the  living 
larvae  had  been  applied.  Within  twenty-four  hours  an  itch- 
ing, vesicular  eruption  had  developed,  followed  by  pustules 
exactly  resembling  those  found  in  the  lesions  of  ground  itch. 


80 


HOOKWORM  DISEASE. 


In  all  tlie  other  cases  no  such  lesions  appeared.  A  re- 
examination of  the  mud  showed  that  the  live  worms  had 
disappeared,  but  that  the  dead  ones  were  still  present.  The 
live  worms  had,  therefore,  apparently  entered  the  skin,  and 
their  entry  had  been  followed  by  lesions  and  symptoms  sim- 
ilar to  ttiose  of  water  sore  or  ground  itch. 

These  experiments  with  ankylostoma  have  been  paral- 
leled by  the  brilliant  work  of  Claude  A.  Smith,  and  the  re- 
sults found  to  hold  good  for  uncinaria  Americana.  He 
placed  mud  containing  encysted  larvse  on  the  arm  of  a  man 


Pig'.  18.  Experimental  hookwoi'm  infection.  Sliows  1,348  uncinarite  re- 
moved from  the  intestines  twelve  weeks  after  the  eruption  on  the  wrist. 
(Photograph  furnished  by  Dr.  Claude  A.  Smith.) 


not  previously  infected  and  allowed  it  to  remain  one  hour. 
In  eight  minutes  itching  was  complained  of,  and  on  remov- 
ing the  soil  a  macular  eruption  was  present.  The  next  day 
the  wrist  was  swollen.  On  the  following  day  a  vesicular 
eruption  was  present,  and  much  itching  was  complained  of. 
On  the  fifth  day  the  vesicles  had  become  confluent,  the 
swelling  increased,  and  the  axillary  glands  enlarged  and 
tender.  The  twelfth  day  no  sign  of  the  dermatitis  re- 
mained. On  the  eighth  day  an  attack  of  sore  throat,  with 
fever,  developed.     During  the  next  three  weeks  an  uneasy 


MODES  OF  INFECTION.  81 

feeling  about  tlie  stomach  was  complained  of.  Ova  ap- 
peared in  the  stools  at  the  middle  of  the  seventh  week.  A 
small  particle  of  mud  was  applied  without  the  patient's 
knowledge  to  the  prepuce  of  a  man  about  to  be  circumcised. 
In  four  minutes  he  remarked  that  he  felt  as  though  a  fly 


Pig.    19.      Section    of    sicin    as    seen    under    tlie    microscope,    showing"    tlie 
hookworm  larvse  crawling  through  the  sliin.      (After  Stiles.) 

was  crawling  over  the  part,  and  in  a  minute  longer  said  he 
felt  as  though  his  prepuce  was  being  pricked  with  needles. 
In  four  minutes  the  larvae  had  left  the  mud,  as  shown  by 
subsequent  examination,  but  under  a  low  power  lens  the 
skin  was  seen  covered  with  them. 


82  HOOKWORM  DISEASE. 

Smith  was  also  able  to  produce  lesions  resembling  ground 
itch  by  applying  an  alcoholic  extract  of  uncinaria  larvae, 
though  aqueous  and  ethereal  extracts  gave  negative  results. 

Sections  of  the  skin,  removed  and  hardened  even  in  a  few 
minutes  after  infectious  larvae  have  been  applied,  show 
numerous  larvae  in  the  hair  follicles,  sweat  ducts,  and  al- 
ready actually  in  the  tissues.  In  sections  prepared  after  a 
longer  time  has  elapsed  many  larvae  can  be  found  deep  in 


Pig.   20.      Larvae   in  axillary   gland.      (After   Stiles.) 

the  skin  and  subcutaneous  tissue,  some  of  which  may  now 
be  found  in  caiDillary  blood  vessels.  They  possess  wonder- 
ful ability  to  plow  through  any  kind  of  tissue  in  the  en- 
cysted stage,  but  will  not  attemjot  to  penetrate  the  skin  be- 
fore this  stage  is  reached.  Once  in  the  blood  stream,  they 
are  carried  to  the  right  heart.  Sections  have  been  made  in 
which  the  larvae  were  found  in  blood  in  the  heart  cavity. 
(Fig.  21.)  From  the  heart  they  are  carried  by  the  blood 
stream  to  the  lungs.  Here  they  are  caught  in  the  capillaries, 
because  they  are  so  much  larger  than  the  smallest  capil- 
laries of  the  lungs  and  can  not  i:»ass  through.     Meeting  with 


MODES  OF  INFECTION".  83 

obstruction,  they  again  exercise  their  ability  to  penetrate 
tissue  and  soon  get  into  the  bronchial  tubes, 

Ashford  and  King  infected  the  skin  of  a  young  guinea  pig 
with  a  very  heavily  infected  culture,  and  in  three  hours  the 
animal  died.  Autopsy  showed  one  lung  solidified  with 
blood  and  the  other  one  contained  many  larger  or  smaller 


'*\ 


• 


'  ..v 


1 J I  I I 

200  A^ 


Fig-.  21.     A  liookworm  larva  in  tlie  blood  in  the  heart.      (After  Stiles.) 

hemorrhagic  spots.     Sections  showed  numerous  uncinaria 
larvae  in  these  accumulations  of  blood. 

After  the  larvae  reach  the  bronchi  they  are  carried  to  the 
mouth,  either  as  a  result  of  the  normal  constant  outward 
current  of  the  bronchial  and  tracheal  mucous  membrane 
or  by  coughing.  No  doubt  many  of  them  are  now  spit  out, 
but  some  are  swallowed.  More  or  less  larvae  would  be 
swallowed,  according  to  whether  the  individual  spits  out 
what  he  coughs  up.  Habits  vary  much  in  this  regard,  as 
is  well  known.  No  doubt  this  is  an  important  factor  in 
determinino'  the  extent  of  infection  in  different  individuals 


84 


HOOKWORM  DISEASE. 


equally  exposed,  and,  in  view  of  this  idea,  it  seems  wise  to 
advise  patients  who  have  ground  itch  not  to  swallow  their 
sputum. 


'"    ■.■::..i>i; 

ft'! 

":d0 

•■  1 

■-'         ^        LH'WiKER,  W 


Fig.  22.      Two  hookworm  larvae  in  the  lungs.     The   one  on   the  left  is  en- 
tering the  bronchus.      (After  Stiles.) 

Larvae  that  are  swallowed  pass  through  the  stomach,  re- 
sisting the  gastric  juice  just  as  they  resist  other  chemicals, 
sulphuric  acid,  bichloride  of  mercury,  etc.,  and  when  they 


iHwiLoeii 


Fig.  23.     Larvae  wandering  up  the  trachea.      (After  Stiles.) 


MODES  OF  INFECTION.  85 

reach  the  small  intestine,  the  natural  home  of  the  parasite, 
they  undergo  further  development. 

Four  or  five  days  after  the  larvag  reach  the  small  intestine 
another  ecdysis  begins,  in  which  they  acquire  a  buccal  cap- 
sule. With  this  capsule  the  worm  fastens  on  to  the  mucous 
membrane  by  sucking  in  a  plug  of  epithelium,  which  fur- 
nishes his  nourishment.  In  another  four  or  five  days  the 
last  ecdysis  begins  and  the  last  skin  is  shed.  The  worms, 
about  one-fifth  of  an  inch  long,  now  grow  rapidly,  and  in 


^(■^ 


mt-mm 


Fig-.  24.      Two  larvae  in  tlie  larynx.      (After  Stiles.) 

six  to  eight  weeks  from  the  original  infection  they  begin 
to  lay  eggs,  which  are  discharged  with  the  feces  of  the 
patient. 

That  infection  through  the  skin  is  possible  from  short 
contact  with  infected  mud  and  water  is  proved.  Every  step 
and  stage  of  this  process  has  been  demonstrated  by  several 
independent  workers.  Accepting  this  fact,  it  is  only  neces- 
sary to  consider  how  much,  in  the  lives  of  people  who  have 
hookworm  disease,  their  skins  are  exposed  to  dirt  and 
water  containing  appreciable  amounts  of  material-contain- 


86  hookwobjsi  disease. 

iug  feces  to  realize  the  much  greater  opportunity  for  skin 
than  mouth  infection. 

Disposition  of  Feces. 

How  feces  are  disposed  of  and  disseminated  in  localities 
in  which  hookworm  disease  is  prevalent.— Hookworm  dis- 
ease is  pre-eminently  a  rural  disease,  being  limited  in  large 
cities  to  imported  cases,  those  infected  away  from  home, 
and  a  few  cases  infected  in  the  suburbs.  The  disease  is 
prevalent  among  inhabitants  of  small  towns  and  those  liv- 
ing on  the  outskirts  of  the  town,  especially  in  the  poorer 
classes  of  people,  where  the  same  conditions  conducive  to 
infection  exist  as  in  the  country,  but  to  a  less  degree.  The 
chief  sources  of  infection  for  city  people  are  visits  to  coun- 
try towns,  farms,  and  rural  health  resorts.  Children,  es- 
pecially, often  go  to  the  country  for  their  health,  and  return 
infected  with  blood-sucking  parasites,  which  may  continue 
to  reduce  their  vitality  and  health  for  from  seven  to  twelve 
years.  City  children,  however,  are  less  likely  to  become 
infected  than  the  country  children  in  the  same  place,  be- 
cause they  are  not  so  likely  to  go  barefoot. 

In  the  country  there  are  few  privies.  With  the  better 
class  of  farm  and  other  country  families  and  in  towns 
privies  are  more  generally  used.  The  objects  in  the  con- 
struction of  the  privy,  however,  in  general,  in  town  and 
country  are  only  shelter  and  convenience,  and  the  sanitary 
disposal  of  the  feces  receives  no  consideration.  We  have 
indeed  seen  very  few  privies  in  country  or  town  that  were 
not  open  at  the  back,  leaving  the  feces  just  as  accessible  to 
hogs,  chickens,  etc.,  as  if  no  privy  had  been  used.  The  ani- 
mals root  and  scratch  the  feces,  and  thus  scatter  them  about 
over  the  ground.  Not  only  this,  but  they  often  eat  feces, 
which  pass  through  their  digestive  tract,  a  part  being 
digested,  but  the  undigested  material  is  passed  many  hours 


MODES  OF  INFECTION. 


87 


later,  often  a  distance  from  the  privy.  If  the  feces  eaten 
by  such  animals  contain  hookworm  ova,  they  pass  through 
undigested  and  are  thus  widely  distributed.  We  are  not  in- 
formed of  any  experiments  to  show  whether  ova  will  resist 
the  digestive  process  of  other  animals,  but  we  have  recently 


Fig.  25.     A  privy  from   which   soil  pollution   is  being,  spread  by  chickens 
and  swine.      (After  Stiles.) 

made  the  following  experiment  with  the  chicken:  A 
chicken's  feces  were  examined  and  found  not  to  contain 
hookworm  eggs.  A  quantity  of  feces  containing  many  un- 
cinaria  Americana  eggs  were  fed  to  the  fowl  through  a  tube. 
In  thirty-six  hours  the  chicken's  feces  were  found  to  con- 


88 


HO(JKWORM  DISEASE. 


tain  many  uncinaria  eggs,  which  appeared  unchanged. 
Some  of  this  material,  mixed  with  charcoal  and  sand,  was 
incubated,  and  in  twenty-four  hours  larvae  began  to  hatch 
out.  This  proves  that  the  chicken  may  scatter  infected 
feces.     Chickens  will  eat  fresh  human  feces  when  thev  have 


Fig.  26.     A  privy  in  the  center  of  a  town  of  about  2,000  population. 


a  chance,  and,  besides  this,  they  scatter  them  abuut  on  their 
feet  after  scratching  in  them. 

When  the  location  of  a  privy  is  under  consideration,  if 
such  a  place  is  available,  a  hill  side  or  sloping  joiece  of 
ground  is  usually  selected.  It  results  that  heavy  rains 
wash  the  feces  from  under  the  privy,  carrying  them,  and 
others  scattered  by  domestic  animals,  into  mudholes, 
ditches,  etc.  Later  the  barefoot  boy  comes  along  and 
wades  or  plays  in  the  water  or  ditch.     The  result  will  be 


MODES  OF  IXFECTIOX, 


89 


infection  if  tlie  feces  deposited  contain  ova.  Only  those 
who  have  had  proper  opportunity  to  observe  the  facts, 
chiefly  by  residence  on  the  farm  and  in  the  country,  will  be 
able  to  realize  fully  the  possibilities  along  this  line. 

Where  do  the  60  to  80  percent  of  rural  population  who 
have  no  privies  deposit  their  feces,  and  what  becomes  of 
them?     This  varies  very  much  with  the  people,  the  loca- 


Fif 


'.7.     The  kind  of  privy  in  general  use  in  small   towns. 


tion,  their  occupation,  and  local  and  family  habits.  Our 
own  observations  of  these  things  were  made  during  many 
years  of  residence  in  the  country,  where  the  class  of  people 
and  habits  and  conditions  are  such  as  to  induce  infection  of 
a  large  percentage  of  the  population.  The  adults,  and 
often  the  children,  of  these  families  usually  go  to  the  barn- 
yard or  to  the  garden  behind  the  house,  or  to  "the  bushes," 


90  HOOKWORM  DISEASE. 

or  to  "the  thicket"  if  one  is  near  by,  or  behind  anything 
like  stumps,  trees,  hills,  or  outhouses,  that  will  hide  them 
from  the  house.  Often  nobody  else  lives  in  sight,  so  it  is 
only  necessary  to  hide  from  members  of  their  own  family, 
regarding  which  they  are  usually  not  particular. 

The  children  around  a  place  not  provided  with  a  privy 
frequently  do  not  get  as  far  away  from  the  house  as  the 
adults,  especially  the  men.  It  is  often  possible  to  deter- 
mine the  number  of  children  in  a  family  by  the  number  of 
piles  of  feces  in  the  back  yard.  In  the  latter  part  of  the  day 
they  are  found  partially  or  completely  eaten  up  by  chickens, 
ducks,  and  dogs,  by  which  it  is  possible  that  eggs,  if  present, 
are  again  more  widely  distributed  over  the  premises. 

Many  of  the  men  in  the  country  deposit  their  feces  in 
almost  any  convenient  hiding  place  near  their  work.  The 
farm  laborer  drops  his  work  whenever  the  desire  seizes  him, 
and  goes  to  "the  bushes,"  or  the  "fence  jam,"  or  "the 
gully"  to  relieve  himself.  The  coal  burner,  belonging  to 
the  worst  infected  class  of  people  in  the  timber  sections  of 
many  of  the  southern  states,  defecates  behind  stumps  near 
his  coal  kiln,  around  which  he  lies  and  attends  for  thirty  or 
forty  days,  often  barefoot.  His  children  play  around  his 
working  j^lace  much  of  the  time,  and  assist  him  to  pollute 
the  soil  and  share  the  results  with  him.  Around  saw  mills, 
public  works,  etc.,  the  laborer  usually  repairs  to  some  com- 
monly used  thicket  or  hiding  place  to  deposit  his  feces  on 
the  ground.  In  small  towns,  where  many  country  people 
come  to  market,  etc.,  there  is  often  some  nearby  thicket,  or 
gully,  or  barnyard  to  which  the  country  people  go  when 
they  get  "in  a  tight,"  in  preference  to  privies,  to  which  they 
are  unaccustomed,  even  if  they  are  available.  The  country 
people  are  more  or  less  infected,  and  they  thus  convert  these 
resorts  into  veritable  hotbeds  of  hookworm  larvae.  During 
a  rainy  spell  the  barefoot  boy  who  runs  around  in  this 


MODES  OF  INFECTION.  91 

locality  is  sure  to  cry  with  ground  itch  the  next  few  nights. 
AVe  remember  such  a  "gully"  near  a  country  town,  and, 
with  our  present  information  of  the  disease  and  knowledge 
of  the  prevalence  of  it  among  the  country  people  of  that 
section,  we  now  see  ample  explanation  for  the  ground  itch 
and  anemia  among  many  of  the  town  boys  who  often  went 
barefoot  in  warm  weather.  The  most  favored  parts  of  the 
''gully"  were  so  much  used  for  this  purpose  that  there 
often  seemed  to  be  no  more  room. 

Many  of  the  country  schools  are  not  provided  with  any 
sort  of  a  privy,  and,  often  when  they  are,  the  latter  are  not 
much  used,  because  the  children  are  not  accustomed  to  them 
at  home.  Usually  in  such  instances  the  girls  go  to  one 
place  and  the  boys  to  another,  chosen  by  a  kind  of  natural 
selection.  A  thick  clump  of  bushes,  a  gully,  or  a  hollow 
behind  a  hill  are  the  places  usually  selected.  A  large  per- 
centage of  the  pupils  in  such  schools  are  often  infected. 
They  pollute  the  soil,  which  becomes  a  source  of  infection 
and  reinfection  of  all  the  barefoot  children  who  visit  it 
during  a  hot,  wet  spell.  We  recall  many  schools  and 
churches  in  a  country  in  Avhich  much  hookworm  disease 
exists,  where  the  sanitary  conditions  were  exactly  as 
described.  Ground  itch  was  a  common  trouble,  and  every 
boy  knew  what  it  was — most  of  them  from  oft-repeated 
personal  experiences.  The  coming  of  railroads,  develop- 
ment of  the  country,  and  introduction  of  people  accustomed 
to  the  use  of  privies,  and  to  more  general  wearing  of  shoes, 
has  reduced  the  anemia,  once  very  prevalent,  to  an  appreci- 
ably smaller  degree. 

Miners  working  sometimes  deep  underground  often  defe- 
cate in  the  mine,  usually  in  some  corner  not  being  worked  at 
the  time.  The  temperature  and  moisture  are  favorable  for 
hatching  and  development  of  the  infectious  larvae.  Mud 
and  water  of  the  mine  become  infected,  and  frequently  get 
on  the  hands  and  feet  of  the  laborer. 


92  HOOKWOEM  DISEASE. 

A\^e  have  seen  that,  in  the  case  of  the  class  of  people  who 
are  infected,  their  feces  are  pretty  widely  scattered  about 
where  they  work  and  stay.  It  is  only  necessary  to  call  at- 
tention to  the  very  general  practice  of  these  people  of  going 
barefoot  during  the  summer.  This  often  is  not  realized  by 
the  city  resident,  who  seldom  sees  barefoot  j^eople.  The 
children  go  barefoot  often  until  they  are  fourteen,  fifteen 
or  more  years  old,  and  often  during  the  warmest  weather 
the  adults  of  the  family  enjoy  this  pleasure  and  saving  also. 
They  wear  their  shoes  when  ihej  go  away  from  home;  so 
one  must  see  them  at  home  to  see  them  as  they  really  are. 
In  these  rural  districts  where  shoes  are  not  so  generally 
worn  we  have  often  seen  children,  and  even  grown  people, 
walking  to  church  barefoot,  carrying  their  shoes  in  their 
hands  or  on  their  shoulders.  Their  Sunday  shoes  often 
hurt  their  feet,  which  are  unaccustomed  to  shoes.  When 
they  get  near  the  church  they  sit  down  by  the  roadside  and 
put  on  their  shoes.  These  facts  will  be  verified  by  anybody 
familiar  with  the  habits  and  customs  of  the  inhabitants  of 
these  remote  rural  districts  where  hookworm  disease  flour- 
ishes most. 

It  must  be  remembered  that  the  conditions  of  shade, 
moisture,  and  favorable  temperature  required  for  the  ex- 
tensive development  of  the  larvae  to  the  infectious  stage 
occur  only  a  few  times  a  year — during  long  rainy  spells. 
These  wet  spells  also  furnish  the  condition  in  which  the 
barefoot  individual  has  more  or  less  mud  and  water  on  his 
feet  all  day.  Those  who  wear  shoes  step  in  mud  and  water 
that  may  run  in  leaky  shoes.  If  such  mud  and  water  con- 
tains larvae,  they  will  reach  the  foot  in  this  way.  The  pos- 
sibility of  infection  through  wet  shoes  free  from  holes  is 
suggested  by  a  recent  experiment  made  by  Bass.  He  placed 
a  culture  of  encysted  uncinaria  Americana  larvae,  grown  in 
a  mixture  of  feces  and  charcoal,  on  one  side  of  the  arm  part 


MODES  OF  INFECTION.  93 

of  a  kid  giove  that  had  been  soaked  in  water.  On  the  oppo- 
site side  he  placed  some  mud  made  of  sterile  soil  and  water. 
After  three  hours  the  mud  was  removed,  and  on  examina- 
tion four  living  and  two  dead  larvas  were  found  in  it.  Walk- 
ing in  infected  mud  would  furnish  similar  conditions,  and  it 
is,  we  believe,  possible  that  infection  may  occur  in  this  way. 
It  is  possibly  an  ex]3lanation  of  the  few  cases  of  hookworm 
disease  in  people  who  do  not  know  of  having  had  ground 
itch. 

It  has  been  seen  that  experimental  inoculation  with  un- 
cinaria  larvae  gives  rise  to  sym^Dtoms  identically  like  those 
of  ground  itch  or  dew  poison.  Ashford  and  King  obtained 
a  history  of  ground  itch  in  90  percent  of  their  cases.  This 
condition  is  not  so  clearly  described  technically  for  the 
diagnosis  to  carry  with  it  any  clear  cut  picture  or  idea  of 
disease  to  the  uninitiated,  but  every  country  boy,  or  man 
who  was  a  country  hoj,  knows  what  ground  itch  or  toe  itch 
is,  and  to  him  these  terms  mean  a  definite  clinical  condition, 
which  he  knows  when  he  sees  or  feels  it.  We  have  not  ac- 
curate tabulation  of  our  cases  with  relation  to  this  symp- 
tom, but  we  have  made  it  a  point  to  inquire  about  it  in 
several  hundred  cases.  We  are  certain  over  75  percent 
gave  a  history  of  having  had  it.  Onh^  mild  cases  give  a 
negative  history,  and  probably  had  infections  too  mild  for 
them  to  recognize  as  the  ground  itch. 

We  believe  we  are  justified  in  concluding  that  the  real 
source  of  hookworm  infection  is  always  the  feces  of  in- 
fected persons,  and,  further,  that  the  onlj-  practical  mode 
of  infection  is  by  the  skin.  AYalking  barefoot  in  infected 
mud  and  water  is  the  chief  way  in  which  infection  gets  to 
the  skin.  Proljably  next  in  importance  is  infection  through 
leak}^  and  wet  shoes.  Other  modes  of  infection  are  pos- 
sible, and  no  doubt  do  occasionally  occur,  but  compara- 
tively they  are  of  little  importance. 


CHAPTER  V. 

PATHOLOGIC  ANATOMY  AND  PATHOLOGY. 

The  anatomic  changes  caused  by  hookworm  can  be  partly 
studied  during  life  in  the  blood,  and  the  changes  in  that 
fluid  will  be  briefly  described  in  this  chapter  on  account  of 
their  close  relation  to  the  theories  of  the  disease.  The  con- 
dition of  the  blood  is  also  referred  to  in  greater  detail  in 
Chapter  VI,  among  the  syni23toms  of  the  disease. 

Post-Mortem  Appearances. 

Skin. — The  skin  of  a  hookworm  subject  is  pale,  sallow,  or 
even  lemon  color,  and  waxy,  so  that  the  l)ody  may  resemble 
a  wax  figure.     (Ashford  and  King.) 

The  body  shows  varying  states  of  development,  as  will  be 
described  more  fully  under  symj)toms.  Emaciation  is  not 
always  marked,  as  Wucherer  noted.  The  subcutaneous  fat 
is  often  well  preserved,  pale,  and  yellow.  The  mesentery, 
omentum,  mediastinum,  and  pericardium  are  often  unusu- 
ally fat.  The  muscles  are  jDale,  sometimes  brownish  gray 
(Ashford  and  King),  soft,  friable,  and  bloodless.  All  the 
organs  show  great  lack  of  blood.  Serous  etfusions,  on  the 
other  hand,  are  usually  present.  They  are  most  frequent 
and  most  marked  in  the  abdominal  cavity  and  lower  ex- 
tremities, but  general  anasarca  is  also  sometimes  present. 
Straw-colored  fluid  may  be  found  also  in  the  pleural  cavi- 
ties, pericardium,  and  ventricles  of  the  brain,  and  there  is 
not  infrequently  edema  of  the  lungs.  Sand  with  saw  edema 
of  the  glottis. 

The  heart  is  sometimes  small,  but  generally  enlarged, 
dilated,  and  with  more  or  less  secondary  hypertrophy,  es- 

94 


PATHOLOGIC  ANATOMY  AND  PATHOLOGY.  95 

pecially  of  the  left  ventricle.  The  subepicardial  fat  is  often 
well  preserved.  Post-mortem  coagula  may  be  either  soft 
and  red,  or  pale  and  gelatinous,  and  the  heart  cavities  and 
arteries  may  also  contain  pale  liquid  blood.  Accidental 
valvular  lesions  are  sometimes  found;  more  frequently  there 
are  dilatations  of  the  tricuspid  and  mitral  valve  from  mus- 
cular weakness.  Sandwith  found  the  mitral  markedly 
changed  in  12  percent  of  cases. 

The  heart  muscle  is  flabby,  pale,  sometimes  showing  small 
or  even  large  bright  yellow  areas  on  transverse  section  of 
the  papillary  muscles. 

There  is  often  sclerosis  of  the  arteries,  even  in  young  sub- 
jects. Similar  changes  may  affect  the  cardiac  valves,  es- 
pecially the  mitral.  Ashford  and  King  have  observed  such 
changes  with  only  slight  anemia. 

The  lungs  are  bloodless  and  often  edematous,  as  stated 
above,  and  sometimes  the  seat  of  hypostatic  congestion. 

The  spleen  is  usually  not  enlarged,  sometimes  small,  soft, 
and  with  wrinkled  capsule.  Sandwith  found  it  enlarged  in 
one-third  of  his  cases  in  Egypt.  It  is  sometimes  tough, 
sometimes  friable.  In  the  pulp  large  numbers  of  eosino- 
phile  cells  may  be  found.     (Yates.) 

The  kidneys  are  pale  and  large;  the  capsule  strips  easily 
and  shows  a  mottled  anemic  surface;  the  cut  section  is 
slightly  fatty  looking,  and  often  shows  traces  of  parenchy- 
matous or  interstitial  inflammation  and  fatty  degeneration. 
The  kidneys  are  sometimes  amyloid.  Sandwith  finds  the 
changes  so  typical  as  to  suggest  the  term  "ankylostoma 
kidney."  Granular  contracted  kidneys  with  cysts  are  often 
noted,  but  are  accidental  findings. 

The  liver  is  usually  not  greatly  enlarged,  but  rarely 
smaller  than  normal,  pale  or  bright  yellow,  or  brownish  or 
greenish  yellow,  and  greasy  looking.  The  tissue  is  brittle 
and  fatty.     Amyloid  degeneration  is  rare.     Daniels  found 


96  HOOKWORM  DISEASE. 

an  excess  of  iron-containing  pigment,  but  Gutierrez  could 
not  confirm  this.  Yates,  in  a  severe  case,  found  necrosis 
about  the  central  veins. 

The  pancreas  shows  no  constant  change.  Some  authors 
have  thought  it  enlarged. 

The  stomach  is  often  dilated,  sometimes  enormously  so, 
especially  in  countries  where  bulky  diet  is  the  rule.  Chronic 
gastritis  in  various  degrees  is  commonly  found.  Hemor- 
rhagic erosions  have  been  described  by  Eoth.  Ashford  and 
King  occasionally  found  hookworms  free  in  the  cavity  of 
the  stomach,  and  Gutierrez  found  several  adherent.  But- 
terworth  (Journ.  Amer.  Med.  Assn.,  Aug.  21,  1909)  has 
reported  a  case  in  which  a  large  hair  cast  was  found  in  the 
stomach  of  a  girl  8  years  old  severely  infected  with  hook- 
worm. 

Intestines. — Sometimes  dark  red  or  slate-colored  areas 
can  be  seen  through  the  serosa,  and  sometimes,  but  rarely 
on  the  whole,  blood  may  make  the  intestine  look  dark.  In 
severe  cases  of  long  standing,  however,  these  may  not  be 
present,  so  that  Ashford  and  King  did  not  find  even  bloody 
mucus.  Apparent  contractions,  such  as  AVucherer  de- 
scribed, are  for  the  most  part  accidental,  but  thinning  of 
the  walls  is  likely  to  occur  in  severe  chronic  cases,  and 
Craig  saw  almost  complete  obliteration  of  the  valvulae 
conniventes. 

In  the  examination  of  hookworm  subjects  for  exact  scien- 
tific purposes  it  is  advisable  to  make  the  autopsy  as  early 
as  possible,  and  the  body  should  not  be  chilled,  as  the  hook- 
worms are  more  likely  to  remain  alive  in  the  warm  body. 
The  inspection  of  the  intestines  should  be  made  first,  after 
opening  the  body.  The  intestine  may  be  ligated  in  small 
lengths,  and  each  length  opened  in  a  vessel  of  warm  water. 
The  sections  of  intestine  may  at  once  be  placed  in  preserv- 
ing solutions,  and  the  contents  of  the  intestine,  with  the 


PATHOLOGIC  ANATOMY  AND  PATHOLOGY.  97 

warm  water  in  wliicli  the  gut  was  opened,  examined  for  free 
worms.  In  the  majority  of  cases  it  is  enough  to  o^Den  the 
intestine  carefully  on  a  flat  surface  and  spread  it  out  for  in- 
sjDection  before  washing  it  with  water. 

The  contents  of  the  duodenum,  jejunum,  and  even  the 
ileum  are  sometimes  blood-stained.  Besides  the  blood  and 
the  usual  material,  there  is  an  excess  of  mucus,  worms,  and 
ova,  and  Charcot's  crystals. 

The  mucosa  is  often  covered  with  thick  tenacious  mucus, 
sometimes  stained  red  to  chocolate  color  by  blood.  The 
Peyer's  patches  and  solitary  nodules  are  often  swollen. 
Ecchymoses  and  small  erosions  are  frequent  in  the  experi- 
ence of  most  observers,  varying  from  3  to  4  millimeters  in 
diameter  or  even  larger.  In  some  cases  they  are  very  nu- 
merous, giving  a  speckled  appearance  to  the  mucosa,  as 
Whipple  states.  The  lesions  are  usually  the  same  level  as 
the  surrounding  tissue,  but  may  be  swollen,  as  in  the 
frontispiece.  In  the  midst  of  the  red  area  is  a  small  23ale 
elevation,  at  the  summit  of  which  the  worm  may  be  seen 
adhering,  or  the  hole  caused  by  its  bite  after  the  worm 
has  fallen  away.  There  may  be  considerable  dark  red  or 
slate-colored  pigmentation  around  the  lesions,  from  old 
congestion  and  hemorrhage,  and  dense  induration  of  the 
wall.  Strong,  and  also  Yates,  found  extensive  eosinophile 
infiltration  in  the  mucosa,  submucosa,  and  even  the  muscu- 
lar coats. 

The  hookworms  are  found  in  various  parts  of  the  small 
intestine,  from  the  stomach  to  the  lower  ileum.  Ashford 
and  King  found  most  in  the  upper  and  middle  part  of  the 
jejunum;  Allen  J.  Smith  in  the  duodenum,  jejunum,  and 
upper  part  of  the  ileum;  Tenholt  in  the  lower  part  of  the 
small  intestine;  Sandwith  within  2  meters  of  the  pylorus, 
as  a  rule — the  lowest  6.30  meters.  In  one  case  he  found 
1,353  out  of  1,524  worms  in  the  first  two  meters  of  the  gut. 


98  HOOKWOEM  DISEASE. 

They  are  found  free  or  attached,  varying  much  according 
to  circumstances.  Sandwith  in  one  case  found  ' '  217  out  of 
863  worms  attached  to  the  mucosa;  645  were  free,  16 
were  alive,  and  one  couple  in  copulation."  Ashford  and 
King  and  their  colleagues  in  Porto  Eico  did  not  find  many 
attached.  In  one  case  they  found  83  in  the  stomach  ('' pos- 
sibly dislodged  in  the  manipulation"),  163  in  the  duo- 
denum, and  the  rest  in  the  jejunum.  In  some  cases  very 
few  worms  are  found  at  autopsies;  Sandwith,  in  a  case  with 
six  bites  in  the  jejunum  and  ileum,  could  find  no  worms. 
As  regards  position  of  the  worms  in  the  intestine,  Sandwith 
suggests  that  in  old  cases  the  duodenum  is  riddled  from 
former  bites,  so  that  the  villi  get  ^' eaten  away"  and  the 
worms  prefer  the  jejunum.  He  found  6  cases  out  of  18  with 
less  than  10  worms,  no  thymol  having  been  given  previ- 
ously. 0.  Baker  explains  the  small  number  of  worms  some- 
times found  post-mortem  on  the  analogy  of  rats  leaving  the 
sinking  ship — not  without  reason,  as  some  other  helminths 
seem  to  leave  their  quarters  in  case  of  severe  illness  of  the 
host.  Sandwith  suggests  that  in  severe  cases  the  "half 
starved  worms  are  dislodged  by  purges  or  repeated  attacks 
of  diarrhea." 

The  ecchymotic  spots  mentioned  above  are  in  some  cases 
up  to  1  centimeter  in  diameter,  or  even  the  size  of  a  silver 
dollar.  In  the  center  of  the  hemorrhagic  spots  the  worms 
are  frequently  found — the  head  and  sometimes  half  the 
body  buried  in  the  mucosa.  The  males  especially  are  fre- 
quently found  almost  buried  in  the  mucosa,  so  that  when 
removed,  an  operation  often  requiring  considerable  force, 
long  narrow  depressions  mark  their  former  positions. 
Sometimes  there  are  minute  holes,  like  pin-pricks,  in  the  red 
areas.  Many  of  the  hemorrhagic  areas  are  without  worms, 
but  show  minute  erosions  or  ulcers  %  millimeter  in  diam- 
eter.    Though    many    observers    have    found    numerous 


PATHOLOGIC  ANATOMY  AND  PATHOLOGY.  99 

hemorrhages,  it  must  be  emphasized  that  they  vary.  Fearn- 
side  found  congested  areas  in  60  percent  of  78  cases. 
Whipple  found  hemorrhages  often.  Looss  found  the  worms 
attached  without  hemorrhages  more  often  than  not,  and  he 
found   hemorrhages   especially  in   recent   cases.     Ashford 


Fig.    28.     Blood   cyst   below    the   mucosa  of  the  jejunum,    with   cross   sec- 
tion (a)   of  included  hookworm.      (After  Whipple.) 

and  King  say  (1904) :  "In  our  autopsies  the  feeding  ground 
of  uncinaria  Americana  can  easily  be  passed  over  without 
being  noted." 

Although  one  might  expect  the  hemorrhages  to  be  in  pro- 
portion to  the  number  of  worms,  there  are  reasons  for 
anticipating  variations  from  a  simple  ratio.  Usually  there 
are  many  more  bites  or  lesions  than  worms.  Sandwith 
found  250  worms  and  counted  575  bites  in  one  case.  Leich- 
tenstern  pointed  out  that  young  ankylostoma  change  their 
position  more  frequently  than  old  ones.    Like  other  hel- 


100  HOOKWORM  DISEASE. 

minths  also,  coitus  is  likel}^  to  be  associated  with  change  of 
location,  and  active  ovulation  with  voracious  feeding,  pos- 
sibly also  with  migration. 

From  the  time  of  Bilharz,  cysts  in  the  submucosa,  con- 
taining blood,  have  been  described.  Whipple  found  them 
not  infrequently,  measuring  5  to  10  millimeters  in  diameter, 
and  gives  photographs  of  sections.  He  also  found  hook- 
worms in  the  cysts  in  7  cases.  The  colon  sometimes  con- 
tains tarry  feces. 

Among  rare  findings  in  the  intestine  may  be  mentioned 
the  perforating  ulcer  of  the  duodenum,  described  by  Wil- 
liams. Wucherer  noted  adhesive  j)eritonitis ;  amyloid  de- 
generation of  the  villi  was  seen  by  Baumler. 

Other  parasitic  worms  are  not  rarely  found  in  cases  of 
hookworm  infection,  especially  ascaris,  oxyuris,  trichiuris, 
and  anguillula.  Ameba  and  other  protozoa  are  not  rarely 
present  in  tropical  and  subtropical  countries,  including  the 
southern  United  States. 

The  bone  marrow  is  pale,  sometimes  lymphoid  and  gray- 
ish red;  sometimes  gelatinous  or  fatty.  In  the  lymphoid 
marrow  nucleated  red  cells  and  other  evidences  of  increased 
blood  formation  are  present. 

The  mesenteric  glands  are  often  hyperemic  and  enlarged, 
and  reach  a  diameter  of  2  or  more  centimeters. 

The  hemolymph  glands  were  found  by  Gutierrez  as  large 
as  hazelnuts,  of  the  type  of  splenolymj^h  glands. 

Edema  of  the  brain  is  not  uncommon  in  severe  cases. 
Meningitis  has  been  observed  sometimes,  with  extensive 
effusions  into  the  ventricles,  as  in  the  child  of  9  years,  de- 
scribed by  Ashford  and  King,  dying  with  8  percent  hemo- 
globin and  720,000  red  corpuscles  per  cubic  millimeter. 

The  changes  in  the  blood,  in  general,  in  cases  that  come 
to  autopsy  are  as  follows:  pale  color,  watery  consistency, 
so  that  the  blood  may  resemble  blood-streaked  serum.     It 


PATHOLOGIC  ANATOMY  AND  PATHOLOGY.  101 

coagulates  slowly  and  imperfectly.  The  specific  gravity  is 
reduced.  The  total  bulk,  according  to  Boycott  and  Hal- 
dane,  is  increased. 

The  hemoglobin  varies  from  a  point  too  low  to  read  in  the 
ordinary  apparatus  to  about  50  percent. 

The  number  of  red  cells  is  reduced,  but  less  in  proportion 
than  the  hemoglobin,  so  that  the  color  index  is  low.  There 
are  rare  exceptions  to  this.  The  red  cells  vary  in  size  and 
shape.  Polychromatophilia,  normoblasts,  microcytes,  and 
macrocytes,  but  rarely  megaloblasts,  occur. 

The  leucocytes  are  usually  increased,  from  twice  to  sev- 
eral times  the  normal,  in  cases  of  comparatively  short  dura- 
tion. In  older  and  very  severe  cases  there  is  sometimes 
leucopenia  of  moderate  degree.  The  leucocytes  are  chiefly 
remarkable  for  the  increase  of  eosinophile  cells,  but  the  pro- 
portion of  them  varies  very  much — up  to  72  percent,  as  in 
a  case  of  Leichtenstern,  and  in  severe  cases,  near  the  end, 
may  be  about  normal  or  even  lower. 

The  blood  changes  in  hookworm  disease,  in  brief,  are 
those  of  secondary  anemia  plus  eosinophilia.  The  state- 
ment so  often  made,  that  the  blood  resembles  that  in  per- 
nicious anemia,  is  based  on  imperfect  knowledge  of  both 
conditions,  and  has  come  down  from  a  time  when  the  blood 
was  examined  much  less  minutely  than  at  present. 

Pathology. 

The  relation  of  the  hookworm  to  the  various  anatomic 
and  functional  alterations  in  hookworm  subjects  is  not  yet 
thoroughly  understood.  The  nearest  and  simplest  explana- 
tion is  that  the  worms  cause  great  and  sometimes  protracted 
loss  of  blood,  and  that  this  interferes  with  nutrition  in 
many  ways  directly  and  indirectly,  including  degeneration 
of  the  walls  of  the  blood  vessels.     The  fact  that  in  some 


102  HOOKWORM  DISEASE. 

cases  with  severe  symptoms  only  a  few  worms  can  be  found, 
and  the  additional  fact  that  even  the  worms  found  do  not 
all  or  always  contain  blood,  have  led  to  a  partial  or  com- 
plete rejection  of  this  explanation,  so  that  others  have  been 
advanced.  ■»  It  is  therefore  necessary  to  examine  the  facts 
and  assign  to  them  their  probable  relations.  That  the 
worms  cause  hemorrhage  can  not  be  doubted  by  any  one 
who  examines  a  number  of  w^orms,  or  who  is  able  to  make 
an  autopsy  on  a  case  that  has  not  had  too  protracted  a 
course.  Such  a  report  as  the  following,  from  Ernst  (1888), 
leaves  no  doubt  as  to  the  presence  of  blood  in  the  intestine : 
' '  On  the  mucosa  of  the  small  intestine  is  an  unusual  amount 
of  tenacious  mucus,  which  even  in  the  upper  meter 's  length 
shows  a  reddish  color  in  some  places;  the  color  becomes 
more  intense  lower  down,  so  that  at  a  distance  of  four 
meters  the  contents  are  a  uniform  dark  chocolate  brown 
tenacious  mass,  the  color  evidently  due  to  blood.  From 
two  meters  below  the  beginning  the  mucosa  shows  numer- 
ous petechial  ecchymoses." 

Such  conditions  are  doubtless  rare,  though  among  reported 
cases  they  are  not  so  rare  as  the  cases  of  advanced  anemia 
examined  by  the  Porto  Rico  Commission  without  finding 
blood  or  ecchymoses  in  the  intestine,  or  blood  in  the  worms. 
Most  observers,  like  ourselves,  find  many  or  most  of  the 
worms  in  any  lot,  especially  the  females,  stained  and  some- 
times stuffed  with  blood,  so  that  they  look  deformed  when 
fixed  in  preserving  fluids  that  cause  much  contraction.  In 
the  dog  hookworms  practically'  all  the  worms  contain  blood. 
The  absence  of  blood  from  the  worms  does  not  prove  that  the 
parasites  did  not  suck  blood,  for  the  ejection  of  blood  has 
long  been  known,  having  been  graphically  described  by 
Ernst  and  Leichtenstern.  These  observers  noted  in  living 
ankylostoma  how  "the  gradually  dying,  but  moving,  worms 
threw  out  of  their  ipouths  at  intervals  clouds  of  red  blood 


PATHOLOGIC  ANATOMY  AND  PATHOLOGY.  103 

corpuscles,  like  a  locomotive  puffing  out  clouds  of  smoke." 
Leichtenstern  saw  this  process  especially  in  worms  from 
acute  cases,  with  severe  anemia  and  rapidly  ensuing  death. 

Whipple  more  recently  writes  that  it  is  ''unusual  not  to 
find  a  few  worms  containing  blood  when  the  autopsy  has 
been  performed  within  two  or  three  hours  after  death." 
''When  worms  full  of  bright  blood,"  he  says,  "were  re- 
moved from  the  intestinal  mucosa  and  placed  in  water  or 
0.8-percent  saline  solution,  they  soon  discharged  the  blood. 
Under  the  microscope  one  could  watch  the  red  blood  cells 
and  blood-stained  fluid  being  poured  out  from  the  mouth 
and  anus.  This  explains  the  fact  that  worms  found  in  the 
feces  or  at  an  autopsy  performed  several  hours  after  death 
may  contain  very  little  or  no  fresh  blood.  "^ 

The  structure  of  the  worms  indicates  that  sucking  is  an 
important  function,  and  it  seems  certain  this  must  have  the 
purpose  of  sucking  fluid.  If  the  worms  fed  mainly  on  epi- 
thelial cells,  as  will  be  discussed  below,  they  would  hardly 
bury  themselves  so  deeply,  nor  suck  into  their  alimentary 
canals  such  masses  of  tissue  as  have  been  described  by 
Looss  and  others.  The  fluid,  then,  must  be  either  blood  or 
blood  plasma,  or  such  other  body  juices  as  can  be  obtained 
in  the  wall  of  the  intestine.  If  the  worms  do  not  use  blood 
as  food,  it  seems  strange  that  they  do  not  exercise  more 
selection  and  reject  it  at  once.  The  process  described  by 
Whipple  is  not,  of  course,  to  be  considered  as  a  wholly 
natural  one.  Even  if,  as  Looss  points  out,  the  blood  cells 
in  the  worms'  intestines  are  not  digested,  it  may  be  ques- 
tioned whether  the  observations  on  that  point  are  final. 
The  observation  quoted  from  Ernst  and  Leichtenstern  sug- 
gests that  the  blood  corpuscles  are  not  chiefly  desired,  but 
the  plasma,  the  digestion  of  which  is  much  more  difficult 


iWhippl*?,   G.    H. :    "Uncinariasis   in   Panama,"  American  Journal  of  tlie  Med- 
ical  Sciences.   July,   1909.  . 


104  HOOKWORM  DISEASE. 

to  observe  than  that  of  the  cells.  Whipple  calls  attention 
to  the  worms  living  in  "worm  cysts"  in  connection  with  the 
matter  of  blood-feeding.  In  these  cysts  the  worms  live  for 
several  days  and  remain  vigorous.  When  the  mucosa  is 
fairly  normal,  as  Whipple  says,  it  is  reasonable  to  suppose 
the  worms  feed  chiefly  on  blood.  When  the  mucosa  is 
anemic,  thickened,  and  infiltrated,  the  worms  may  live 
chiefly  on  the  epithelium  and  mucosa. 

Even  if  the  worms  live  wholly  on  blood  or  blood  plasma, 
the  loss  due  to  their  feeding  in  a  short  time  would  not  need 
to  be  very  great.  According  to  Lutz'  estimates,  1,000 
worms,  a  number  often  present  in  a  single  case,  weigh  4 
grams.  If  each  worm  took  its  weight  of  blood — not  per- 
haps an  inordinate  amount — the  loss  at  one  time  would  be 
trifling,  but,  repeated  day  after  day,  might  easily  be  of  con- 
sequence to  the  host.  It  would  not  be  so  to  a  well-nour- 
ished individual,  consuming  much  more  than  his  need  of 
blood-forming  food,  but  to  one  living  close  to  his  margin  of 
nourishment,  or  with  gastro-intestinal  disease  that  limited 
nutrition,  or  with  insufficiency  of  the  blood-forming  organs, 
it  would  before  long  lead  to  a  definite  anemia. 

But  the  loss  of  blood  is  greater  than  the  greatest  need  for 
food  on  the  part  of  the  worms.  As  was  stated  above,  the 
worms  bite  often  and  in  various  places.  They  cause  a  flow 
of  blood  that  can  sometimes  be  recognized  in  the  stool  by 
the  naked  eye,  or  by  chemical  tests,  and  that  can  often  be 
found  post  mortem.  There  is  evidence  that  worms  them- 
selves produce  a  substance  that  furthers  the  hemorrhage. 
Sabbatani  had  suggested  that  in  many,  perhaps  all,  blood- 
sucking animals  such  substances  exist.  A.  J.  Smith  pre- 
dicted their  occurrence  in  necator.  L.  Loeb  had  shown 
that  the  intestinal  mucous  membrane  and  the  mucus  cover- 
ing it  have  a  strong  effect  in  accelerating  coagulation,  so 
that  ordinarily  bites  like  those  caused  by  hookworm  should 


PATHOLOGIC  ANATOMY  AND  PATHOLOGY.  105 

not  bleed  much.  Loeb  and  Smith  fomid  that  ankylostoma 
caninum  produce  a  substance  that  delays  coagulation;  usu- 
ally for  many  hours,  sometimes  for  twenty-four  hours  or 
longer.  The  substance  was  found  especially  in  the  an- 
terior half  of  the  bodies  of  the  worms,  but  it  could  not  be 
determined  where  it  was  produced — in  the  glands  of  the 
head,  neck,  or  esophagus,  but  probably  the  esophageal 
glands,  as  suggested  by  Smith,  or  the  head  glands.  The 
large  size  of  these  glands  suggests  an  important  function. 
Control  experiments  with  round  worms  and  a  tenia  were 
negative — in  fact  the  coagulation  was  accelerated  by  the 
products  of  the  worms  in  question.  Liefmann  investigated 
with  reference  to  the  presence  of  a  substance  inhibiting 
coagulation  in  ankylostoma  caninum,  but  found  none  in  two 
out  of  three  observations.  He  thought  the  inhibition  was 
brought  about  by  the  co-operation  of  peptone  and  pancre- 
atic secretion.  Loeb  and  Smith  (1906)  deny  this  latter,  for 
various  reasons  not  necessary  to  state.  They  admit  that 
there  may  be  variations  in  the  amount  of  the  coagulation- 
inhibiting  substance  in  different  worms  and  in  different 
lands.  Loeb  and  Smith  also  found  the  substance  was  weak- 
ened by  boiling. 

From  the  biting  and  sucking,  and  the  accidental  hemor- 
rhages, there  is  a  loss  of  blood  in  hookworm  disease  that 
varies  with  the  number  of  worms  and  their  age  and  activity. 
The  loss  will  affect  the  host  partly  in  proportion  to  its  ex- 
tent, but  partly  in  proportion  to  his  resistance  to  the  flow 
of  blood  from  the  bites,  and  partly  to  his  power  to  make 
new  blood.  The  larger  the  number  of  worms,  and  the  less 
active  the  host's  nutrition  and  blood-formation,  the  more 
rapidly  and  more  severely  will  anemia  follow. 

The  process  is  not  unlike  that  seen  in  some  cases  of  bleed- 
ing hemorrhoids  or  gastric  ulcer,  or  other  local  diseases 
with   oft-repeated  hemorrhages.    In  these   we   got   blood 


106  HOOKWOR^M  DISEASE. 

changes  much  like  those  of  hookworm  disease — practically 
identical  in  fact,  with  the  exception  of  eosinophilia — low 
hemoglobin,  low  color  index,  increased  water,  or  so-called 
chlorotic  blood  changes,  poikilocytosis  (with  variations  in 
the  size  of  the  red  cells),  and  sometimes  normoblasts,  but 
rarely  megaloblasts.  Pnfiiness  of  the  subcutaneous  tissue, 
or  even  dropsy  and  anasarca,  follow  as  the  result  of  the 
hydremia.  Nutrition  suffers  in  many  respects — partly  due 
to  the  anemia  and  partly  to  the  consequent  malnutrition  of 
the  blood  vessels. 

Even  the  more  severe  changes  can  be  explained  on  the 
ground  of  prolonged  loss  of  blood.  Compensation  is  main- 
tained as  long  as  possible,  but,  when  the  loss  of  blood  con- 
tinues too  long,  the  blood-forming  organs  may  react  as  they 
do  in  pernicious  anemia  or  in  so-called  aplastic  anemia, 
from  perversion  or  paralysis  of  their  functions. 

The  existence  of  hemolytic  toxins  has  been  assumed  very 
often  in  hookworm  disease  on  account  of  the  discoveries  in 
bothriocephalus  anemia.  But  the  blood  changes  in  the  case 
of  infection  with  the  broad  tape  worm  are  very  different 
from  those  in  hookworm  disease — so  the  analogy  is  not  a 
good  one. 

Gabbi  and  Vadala  (1903),  Goldmann,  Preti  (1908),  and 
others  have  asserted  the  production  of  hemolytic  poisons 
by  hookworms.  Allesandrini  thought  glands  in  the  an- 
terior part  of  the  body  produced  hemolytic  poisons  that 
caused  hyperemia.  Romani,  who  has  done  much  experi- 
mental work,  found  the  serum  of  ankylostoma  subjects 
hemolytic  to  chickens  and  rabbits,  but  not  to  normal  or 
anemic  human  subjects.  He  even  found  the  red  blood 
cells  of  ankj'lostoma  anemia  more  resistant  to  rabbit  serum 
than  those  of  healthy  men,  but,  on  the  other  hand,  the  blood 
serum  of  ankylostoma  subjects  injected  into  the  veins  of 
rabbits  produced  toxic  symptoms  and  hemoglobinuria  in 
smaller  doses  than  the  serum  of  healthy  men. 


PATHOLOGIC  ANATOMY  AND  PATHOLOGY, 


107 


Loeb  and  Smith  (1904)  found  no  evidence  of  hemolysis  in 
extracts  of  dog  hookworms  (ankylostoma  caninnm). 

Whipple  points  out  some  of  the  difficulties  in  the  way  of 
accepting  the  idea  of  hemolysis  from  the  conditions  in  the 
blood  cysts  already  mentioned,  and  shows  the  need  of 
wholly  new  experiments  in  order  to  prove  the  hemolytic 
theory.     As  he  points  out,  the  worms  often  "remain  in 


Fig.    29.     Hookworm   in  thie  submucosa,   with   very   little   extravasation   of 
blood.     Cross  section  of  tlie  body  of  a  female  worm.      (After  Whipple.) 


these  submucus  blood  clots  for  a  few  days  at  least.  The 
worms  are  not  injured  by  their  stay,  yet  there  are  well-pre- 
served red  blood  cells  in  all  parts  of  the  cysts."  The  worm, 
therefore,  "causes  the  loss  of  more  blood  through  damage 
to  the  mucosa  than  it  can  hemolyze  under  favorable  con- 
ditions. It  does  not  seem  likely,  therefore,  that  this  same 
worm  could  secrete  a  hemolytic  substance  which,  taken  up 
by  the  human  intestine,  could  act  on  the  circulating  blood, 


108  HOOKWORM  DISEASE. 

where  conditions  would  be  less  favorable  for  hemolysis  than 
in  the  blood  cysts."  Whipple  has  also  shown  that  the 
worms  contain  a  very  weak  hemolytic  principle  which  is 
active  in  vitro,  but  is  demonstrable  only  in  concentrated  ex- 
tracts of  ^le  hookworm.  Hemolysis  takes  place  very  slow- 
ly, very  little  being  observed  in  six  hours.  The  hemolysin 
is  present  in  all  i^arts  of  the  worm,  and  probably  is  related 
to  its  alimentary  canal  and  its  digestion  of  the  host's  blood. 
Whipple's  observations  on  hookworm  were  controlled  by 
experiments  on  various  other  worms,  dog  hookworm,  whip 
worms,  and  round  worms.  His  negative  findings  confirm 
those  of  Loeb  and  Smith. 

Preti  claims  to  have  discovered  a  hemolysin  in  the  old 
world  hookworm,  not  soluble  in  saline,  but  freed  and  made 
soluble  in  water  by  trypsin.  He  believes  the  substance  is 
similar  to  that  of  bothriocephalus  latus,  but,  as  we  have 
said  before,  the  blood  changes  in  the  two  conditions  are  so 
dissimilar  that  further  proof  and  control  observations  are 
much  needed. 

The  pigmentation  of  the  liver  and  spleen  have  been 
looked  upon  as  evidences  of  a  hemolysin  secreted  by  worms 
and  absorbed  by  the  host,  but,  as  similar  changes  occur  in 
many  secondary  anemias — tuberculosis,  for  example — the 
pigmentation  can  not  be  looked  upon  as  proof  of  a  hemolytic 
poison. 

It  is  necessary  to  discuss  the  other  effects  of  the  hook- 
worms upon  the  intestinal  wall.  Besides  blood,  the  worms 
are  supposed  to  eat  mucus — in  fact,  Sangalli  believed  that 
to  be  their  normal  food. 

Looss  has  shown  a  much  more  important  source  of  food — 
the  intestinal  mucosa  itself.  He  points  out  that  the  worms 
do  not  merely  bore  into  the  intestinal  wall,  as  if  for  the  pur- 
pose of  applying  suction,  but  that  they  cause  an  actual  de- 
fect in  the  tissue.     The  mass  of  tissue,  then,  drawn  into  the 


PATHOLOGIC  ANATOMY  AND  PATHOLOGY. 


109 


esophagus,  as  shown  by  the  beautiful  photographs  of  Looss 
and  the  Porto  Rico  Commission,  is  not  mucosa  alone,  but 
largely  submucosa,  a  plug  of  which  reaches  far  down  the 
esophagus  or  even  into  the  intestine,  in  which  it  can  be  seen 
to  break  down  into  its  histological  elements.  "The  latter 
form  the  exclusive  contents  of  the  intestine  in   the   ma- 


Fig.  30.  Photomicrograph  of  uneinaria  Americana  sucking  mucosa.  By 
the  late  Dr.  W.  M.  Gray,  Washington,  D.  C,  from  the  report  of  the  Porto 
Rico  Commission,   1906-1907. 

jority  of  cases;  in  others  there  is  an  admixture  of  blood, 
which  varies  from  a  few  blood  cells  to  pure  blood.  A  per- 
fect digestion  of  these  corpuscles  does  not  take  place;  the 
nuclei  retain  their  tinctorial  qualities  unchanged,  and  only 
the  plasma  becomes  more  or  less  cloudy.  Accordingly,  the 
intestinal  mucosa  itself  is  the  food  of  the  ankylostoma;  the 
worms  eat  into  it,  and,  if  thereby  they  accidentally  meet  a 


110 


HOOKWORM  DISEASE. 


blood  vessel,  the  wall  of  the  latter  becomes  eroded.  The 
blood  that  flows  out  is  partly  swallowed,  the  rest  escapes 
beside  the  worms,  forming  the  well-known  hemorrhages." 
(Looss.) 

It  is  important  to  realize  the  difference  between  epithelial 
cells  only 'and  the  mucosa,  including  the  sub  mucosa,  which 


Fig.  31.  Jejunum  in  a  fatal  case  of  uncinariasis,  showing  extensive 
scarring  and  inflammation  of  tlie  intestine,  a.  Bases  of  crypts  of  Lieberkiihn; 
many  polynuclear  leucocytes  in  tlie  interglandular  tissue;  b,  muscularis 
mucosae  distorted  and  scarred,  invaded  by  many  wandering  cells,  many  of 
them  eosinophiles;  c,  submucosa,  which  is  much  tliickened  and  full  of  every 
type  of  cell — eosinophiles,  polynuclears,  and  "polyblasts."  There  is  much 
scar  tissue;  new-formed  blood  vessels  are  seen.      (After  Whipple.) 


Looss  thinks  forms  the  food  of  the  worms,  and  we  doubt  if 
the  process  as  described  takes  place  as  often  as  mere  blood- 
sucking. If  it  did,  one  would  expect  to  see  much  more 
serious  defects  of  the  intestinal  walls  in  cases  with,  say, 
1,000  or  1,500  worms,  and  we  should  expect  to  see  the  worms 


PATHOLOGIC  ANATOMY  AND  PATHOLOGY.  Ill 

destroying  or  undermining  the  mucosa,  like  ameba,  but  on 
a  larger  scale. 

An  event  that  must  be  of  greater  importance  than  the 
consumption  of  mucosa  by  the  worms  is  the  infection  of 
the  bites.  This  was  first  emphasized  by  Allen  J.  Smith, 
who  wrote  in  1904:^  ''It  is  possible  too  .  .  .  that  these 
lesions  may  fail  to  heal,  and  from  infection  by  pyogenic 
organisms  become  ulcerated,  small  follicular  ulcers,  with  a 
marked  zone  of  hyperemia,  thus  being  produced.  These 
sometimes  run  together  to  form  irregular  linear  ulcerations 
in  the  mucous  membrane."  The  possibility  of  toxic  ab- 
sorption from  such  ulcerative  lesions  can  not  be  ignored, 
and  Smith  went  on  to  say  that  the  type  of  anemia  and  the 
failure  to  find  hemolytic  poisons  ''by  no  means  set  aside 
the  idea  of  a  toxin  having  widespread  and  important  inter- 
ferences with  the  integrity  of  the  general  tissues  and  of  the 
nutritive  functions  of  the  host. ' ' 

Whipple  believes  that  the  "anemia  may  be  due  to  the 
poisonous  products  absorbed  from  these  foci  of  inflamma- 
tion in  the  intestine,"  and  that  this  explains  the  fact  that 
some  cases  with  relatively  few  uncinariaB  may  show  a  pro- 
found or  even  fatal  anemia.  The  case  he  cites  in  this  con- 
nection is  most  instructive,  and  we  quote  it  in  full,  with 
Whipple's  deductions:^ 

"A  male  Jamaican  negro,  aged  60  years,  shortly  before 
his  death  had  15  percent  of  hemoglobin.  There  was  noth- 
ing unusual  about  the  gross  pathology  of  the  viscera.  The 
tissues  were  all  very  pale.  The  heart  was  greatly  dilated, 
with  watery,  pale  clots — hydremia.  The  lungs  were  pale 
and  cushiony.  The  liver  and  kidneys  showed  a  definite 
yellowish  brown  pigmentation  and  anemia.  The  bone  mar- 
row was  very  firjn,  pink,  and  cellular.     The  jejunum  con- 


1  "TTncinariasis,"    International    Clinics,  vol.  2,  14th  series,  1904,  p.  S2. 
=  Whipple:      "Uncinariasis  in  Panama." 


112  HOOKWORM  DISEASE. 

tained  between  100  and  200  hookworms,  but  the  types  were 
not  identified.  The  mucosa  was  very  pale  and  smooth. 
There  were  no  notes  concerning  the  presence  of  fresh  blood 
in  the  worms,  and  no  notes  regarding  ecchymoses.  We 
can  not  assume  that  the  worms  were  discouraged  by  the 
anemia,  a'bandoned  the  mucosa,  and  were  carried  out  in  the 
feces,  for  we  find  cases  with  even  greater  anemia  and  many 
hundreds  of  worms  in  the  intestines.  Microscopic  sections 
of  this  jejunum  are  most  interesting.  (Fig.  31.)  The 
mucosa  shows  rather  short  villi  and  crypts,  with  a  little  dis- 
tortion of  the  architecture  of  the  glands,  due  to  an  increase 
in  connective  tissue.  The  interglandular  tissue  in  the  villi 
and  at  the  base  of  the  gland  tubules  shows  a  marked  infil- 
tration with  polymorphonuclear  leucocytes  and  eosino- 
philes,  which  in  some  fields  are  more  numerous  than 
the  mononuclears.  The  muscularis  mucosae  is  thickened, 
scarred,  and  infiltrated  with  wandering  cells  of  all  types. 
The  submucosa  is  thickened  and  scarred.  It  is  not  sharply 
separated  from  the  muscularis  mucosse,  and  many  poly- 
morphonuclear leucocytes  and  eosinophil es  are  present. 
Accumulations  of  large  mononuclear  wandering  cells  are 
found  about  the  vessels  in  the  submucosa.  The  outer 
muscle  coats  are  normal.  This  is  a  very  definite  patho- 
logical change,  a  picture  of  diffuse  inflammation,  evidently 
of  some  duration,  due  to  the  hookworm,  as  evidenced  by  the 
eosinophiles. 

''When  one  considers  the  amount  of  tissue  which  was  in- 
volved in  this  change — several  feet  of  the  jejunal  mucosa — • 
it  is  not  difficult  to  account  for  an  advanced  anemia.  Per- 
haps the  same  explanation  may  hold  for  the  liver  necroses 
which  were  present  in  this  case,  and  similar  to  those  de- 
scribed by  Yates  in  a  fatal  case  of  infection  with  the  new 
world  hookworm.  Many  of  the  liver  lobules  show  a  ne- 
crosis of  the  central  half  or  third,  where  the  liver  cells  are 


PATHOLOGIC  ANATOMY  AND  PATHOLOGY.  113 

quite  hyaline,  and  wandering  cells  are  invading  such  areas. 
The  other  liver  cells  show  some  fatty  infiltration  and  a 
deposit  of  a  finely  granular,  yellow  pigment."^ 

Many  efforts  have  been  made  to  isolate  the  poison  of 
hookworms,  but  hitherto  without  results  of  value. 

Lussana  first  thought  he  demonstrated  a  toxic  action  by 
experiments  w^ith  the  urine  of  ankylostoma  patients  in 
animals.  Rabbits  so  treated  developed  anemia.  Arslan  got 
similar  results.  But  such  experiments  are  very  crude,  and 
do  not  permit  definite  conclusions,  so  that  it  is  not  surpris- 
ing to  learn  that  Crisafuli  and  Aporto  got  similar  results 
from  the  urine  of  healthy  men  or  from  those  with  intestinal 
disease.  Vannini  found  the  urotoxic  coefficient  higher  at 
the  height  of  the  disease — 0.88 — than  after  treatment,  and  a 
gradual  fall  to  0.422,  but  this  is  equally  inconclusive. 

Besides  poisons  that  may  be  produced  in  the  lesions  in 
the  intestine,  it  is  possible  that  the  decomposing  blood  ex- 
creted by  the  worms  or  flowing  from  the  bites  may  play 
some  part  in  the  chain  of  events. 

To  summarize  this  part  of  the  subject,  we  suggest: 

1.  That  hookworms  cause  loss  of  blood  by  sucking  and 
subsequent  hemorrhage;  that  this  alone  produces  the 
anemia  in  many  cases. 

2.  That  infection  of  the  bites  is  an  important  part  of  the 
pathology  of  hookworm  disease,  and  may  be  the  most  im- 
portant, either  from  the  number  of  the  lesions  or  the  sever- 
ity of  the  subsequent  bacterial  infection. 

3.  That  other  toxic  processes  may  play  a  part,  but  at 
present  they  have  not  yet  been  proved  to  exist. 

Secondary  anemia  and  toxemia  are  the  only  conditions 
that  could  cause  the  symptoms  in  all  but  advanced  and  com- 
plicated cases,  and  nevertheless  permit  the  rapid  recovery 
that  follows  in  such  cases  on  removal  of  the  worms.     In 


1  In    some    cases    an    actual    mixed     infection   takes  place.     Sabrazes  has  re- 
ported a  striking  example  of  this.     (Arc  h.  de  Med.  exp6r.,  1907,  p.   85.) 


114  HOOKWORM  DISEASE. 

these  it  is  obvious  that  the  lesions  in  the  intestine  are  not 
such  as  could  account  for  the  anemia,  for  in  that  event, 
though  compensation  could  occur,  it  would  hardly  be  so 
closely  related  to  causal  treatment  and  so  rapid  as  the  im- 
provement that  follows  thymol. 

Anemia,  with  its  important  effects  on  all  nutritive  and 
metabolic  processes,  including  oxygen  metabolism,  explains 
most  of  the  striking  features  of  hookworm  disease,  such  as 
the  physical  and  mental  weakness;  it  predisposes  to  other 
diseases,  and  renders  the  patient  more  likely  to  succumb 
to  those  that  affect  the  circulation  when  they  occur  as  com- 
plications. It  may  explain  the  lack  of  development  occur- 
ring in  early  life,  though  this  is  probably  due  even  more  to 
the  local  lesions  in  the  intestine.  A  specific  infl.uence  on 
development  can  not  be  either  asserted  or  denied,  but  it  is 
very  desirable  that  investigations  along  the  lines  suggested 
by  Dr.  I.  I.  Lemann  in  a  case  to  be  reported  be  carried  out 
in  proper  cases. 

The  cause  of  the  eosinophilia  is  almost  certainly  to  be 
ascribed  to  a  toxic  action  by  the  worms,  but  whether  it  has 
any  relation  to  the  other  suspected  toxins  must  be  left  to 
future  observations. 


CHAPTER  VI. 

SYMPTOMATOLOGY. 

There  is  probably  no  disease  in  which  the  symptoms  are 
so  variable  in  degree  as  in  hookworm  disease.  This  is  to  be 
expected  when  the  mode  of  infection,  which  is  fully  dis- 
cussed in  another  chapter,  is  understood.  It  is  certain  that 
every  worm  that  enters  the  body  of  an  individual  comes 
from  without,  and  that  a  patient  can  not  directly  infect 
himself,  because  the  eggs  can  not  hatch  in  the  intestinal 
canal.  The  number  of  worms  that  may  get  into  an  in- 
dividual depends  on  several  very  variable  factors  and  con- 
ditions, and,  in  fact,  frequently  on  accident.  It  follows, 
therefore,  that  the  number  of  worms  present  may  vary  from 
one  up  to  the  lethal  dose  for  the  individual  patient,  which 
frequently  runs  up  into  the  thousands.  Immunity,  both 
racial  and  individual,  also  contributes  to  this  variability  of 
symptoms.  Fatal  cases,  in  which  only  ten  or  twelve  worms 
were  found  at  autopsy,  have  been  reported,  and  other  cases 
have  been  reported  that  expelled  over  4,000  worms,  fol- 
lowed by  complete  recovery.  A  frequent  source  of  vari- 
ability of  symptoms  is  the  presence  of  associated  diseases 
that  produce  more  or  less  anemia  themselves. 
'  The  symptoms  of  hookworm  disease  are  due  to  loss  of 
blood  and  the  effect  of  a  toxin  which  may  also  be  capable 
of  destroying  blood.  This  blood  destruction  results  in 
anemia  of  variable  degrees,  and  this,  in  turn,  gives  rise  to 
other  symptoms,  the  direct  result  of  long  continued  loss  of 
blood.  In  fact,  we  question  whether  the  symptoms  of  hook- 
worm infection  may  not  all  be  attributable  to  this,  except 
possibly  the  eosinophilia  so  frequently  seen.     Certainly  all 

115 


116 


HOOKWORM  DISEASE. 


the   most    prominent    symptoms    are    attributable   to   this 
cause. 

Before  taking  up  the  description  of  symptoms  in  detail, 
we  want  to  impress  on  the  reader  as  forcibly  as  we  can  that 
a  great  mpny  cases  of  hookworm  infection  present  no 
symptoms  that  can  be  recognized  as  variations  beyond  the 


Fig.  32.  Mother  and  three  children,  subjects  of  hookworm  disease. 
Prematurely  old  mother;  youngest  child  also  infected.  (Photograph  fur- 
nished by  Dr.  C.  C.  Thompson,  Columbia,  Miss.) 

normal.  If,  however,  these  patients  with  no  recognizable 
symj)toms  are  cured  of  their  worms,  though  often  very  few 
are  present,  they  frequently  gain  five  or  ten  pounds,  feel 
better  generally,  and  even  show  improvement  of  blood 
count  and  hemoglobin. 


Eecently  we  carefully  measured 


SYMPTOMATOLOGY. 


117 


and  weighed  llfty-six  grown  men  with  hookworm  infection 
so  mild  that  they  could  not  have  been  diagnosed  or  even  sus- 
pected without  a  fecal  examination.  Many  of  them  had  so 
few  ova  in  their  feces  that  none  could  be  found  until  the 
specimens  were  centrifuged.  We  also  weighed  and  meas- 
ured one  hundred  and  twenty-nine  men  of  the  same  class 
who  had  no  infection.     The  infected  averaged  eight  and  one 


Fig.   33.     Family  witli  liookworm  disease  of  moderate  intensity, 
grapii  furnished  by  Dr.  W.  A.  Dearman,  Purvis,  Miss.) 


(Photo- 


quarter  pounds  lighter  and  two  and  one-third  inches  shorter 
than  the  uninfected.  It  is  not  improbable  that  many  of  the 
infected  had  had  greater  infection  in  earlier  life,  and  there- 
fore we  can  not  conclude  that  the  average  of  weight  and 
height  below  that  of  the  uninfected  was  due  to  mild  infec- 
tions altogether.  A  medical  student,  25  years  old,  under 
our    observation    expelled    twenty-two    worms    from    one 


118 


HOOKWORM  DISEASE. 


SYMPTOMATOLOGY.  119 

conrse  of  tliymol,  after  which  no  more  ova  could  be  found. 
He  was  then  as  heavy  as  he  had  ever  been  in  his  life— one 
hundred  and  thirty-seven  pounds.  In  thirty-seven  days  he 
gained  nine  pounds,  and  felt  more  vigorous  and  more  like 
studying  than  he  had  in  his  recollection,  though  he  had 
never  been  sick.  In  fact,  he  said  the  present  treatment  was 
the  first  dose  of  medicine  he  had  ever  taken.  Such  a  pa- 
tient can  not  be  said  not  to  have  had  symptoms,  but  they 
were  not  recognizable.  The  slight  diminution  of  weight 
and  vigor,  though  certainly  present  and  caused  by  the  in- 
fection, was  within  the  normal  variation. 

Another  student  had  a  hemoglobin  percentage  of  100  and 
was  as  red-faced,  healthy  looking,  muscular  a  man  as  was 
in  the  class,  and  played  on  the  football  team  as  a  star.  He 
had  so  few  ova  in  his  feces  that  it  was  necessary  to  use  the 
centrifuge  to  make  the  diagnosis.  Two  months  after  treat- 
ment he  weighed  five  pounds  more  than  he  did  before,  but 
saw  no  difference  in  himself  otherwise.  Many  of  the  mild 
cases  have  slight  reduction  of  hemoglobin,  but  so  many 
other  things  may  cause  the  hemoglobin  to  fluctuate  within 
normal  limits,  and  the  practical  methods  of  estimating 
hemoglobin  are  so  crude,  as  to  prevent  recognition  of  this 
symptom  in  the  mild  cases.  A  reduction  of  hemoglobin  1 
or  2  percent  could  not  be  recognized,  though  actually  pres- 
ent and  caused  by  the  infection.  Ten  or  15  percent  would 
be  considered  within  the  normal  limits.  In  fact,  the  clinical 
methods  of  estimating  hemoglobin  permit  a  variation  of  at 
least  10  percent  from  technical  inaccuracy. 

With  our  present  methods  of  recognizing  the  symptoms, 
we  would  have  to  say  that  many  of  these  mild,  cases  have  no 
recognizable  symptoms  and  can  not  be  said  to  have  hook- 
worm disease.  They  are  classed  as  hookworm  carriers,  but, 
as  we  have  repeatedly  seen,  many  of  them  improve  in 
weight,  feeling,  appearance,  and  hemoglobin  after  getting 


120 


HOOIvWOEM  DISEASE. 


rid  of  what  would  be  considered  an  insignificant  infection. 
We  must,  therefore,  conclude  that  such  cases  have  symp- 
toms, but  that  they  are  so  mild  as  to  be  unrecognizable. 
The  insidious  and  chronic  nature  of  the  disease  prevents  the 


Fig-.    35.     Hookworm    case    of    average    severity;    subject    13    years    old. 
(Photograph  furnished  by  Dr.  H.  H.  Ramsey.,  Darbun,  Miss.) 


patient  from  recognizing  that  his  health  is  impaired.  He 
often  is  healthier  in  every  way  than  others  who  are  well, 
so  far  as  can  be  determined.  One  of  the  symptoms  fre- 
quently seen  in  very  mild  infections  in  adults  is  mild  diges- 


SYMPTOMATOLOGY. 


121 


tive  disturbance,  such  as  slight  reduction  of  digestive 
ability,  tenderness,  and  pain  and  discomfort  in  the  epigas-: 
trium.  These  come  on  so  slowly,  and  often  have  lasted  so 
long,  that  the  patient  does  not  recognize  them  as  symptoms 


Fig.  36.  Same  subject  as  Fig.  35.  Shows  slight  e.dema  of  face  and  ex- 
pression of  illness.  (Photograph  furnished  by  Dr.  H.  H.  Ramsey,  Darbun, 
Miss.) 


of  disease,  but  considers  them  natural.  Let  such  a  patient 
be  cured  of  his  worms,  and  he  notices  at  once  the  change. 
This  type  of  the  disease  in  which  the  symptoms  are  too  mild 
to  be  recognized  when  looked  for  is  usually  caused  by  a 


122 


HOOKWORM  DISEASE. 


small  number  of  worms,  but  occasionally  as  liigii  as  two  or 
three  hundred  worms  may  not  produce  recognizable  symp- 
toms. Adults  who  have  ceased  growing  have  seemed  to  us 
more  susceptible  to  the  effects  of  a  few  worms  than  vigor- 
ous, rapidly  growing  children.  We  are  unable  to  say 
whether  negroes  maj"  joresent  this  type,  but  it  is  quite  cer- 


Fig.    37.     Seven-year    old    girl    with    hookworm    disease.     Small    for    age; 
edema  of  face.      (Photograph  furnished  by  Dr.  H.  H.  Ramsey,  Darbun,  Miss.) 


tain  that  the  small  reduction  of  hemoglobin  could  not  be 
recognized  on  account  of  color.  Their  reputed  relative  im- 
munity makes  it  probable  that  it  would  require  a  greater 
number  of  worms  to  produce  the  same  amount  of  anemia 
and  other  very  mild  symptoms.  This  very  mild  type  of 
the  disease  is,  we  believe,  the  most  common  in  this  country. 


sy:\[ptomatology. 


123 


except  in  the  heavily  infected  regions.  Even  in  the  latter 
there  are  many  of  this  type  among  the  adults  and  the  better 
class,  who  are  less  exposed. 

A  mild  type  of  the  disease  is  next  most  common  in  this 
country.     In  badly  infected  sections  there  are  many  who 


Fig.  38.  Hookworm  case  of  average  severity.  Low  stature,  sloping 
shoulders,  no  mammary  development,  large  abdomen ;  cachectic  face  and 
prematurely  old  expression.  (Photograph  furnished  by  Dr.  H.  H.  Ramsey, 
Darbun,  Miss.) 

show  only  moderate  pallor,  lowered  vitality  and  energy, 
and,  though  the}^  are  not  considered  sick,  their  hemoglobin 
reading  may  be  as  low  as  60  or  70  j^ercent.  Children  with 
this  type  of  the  disease  grow  a  little  less  rapidly  than  their 


1-i  HOOKWOEM  DISEASE. 

fellows.  A  comparison  of  the  weights  and  measurements 
of  several  of  this  type  of  a  given  age  with  a  corresponding 
number  of  uninfected  children  of  the  same  age  always 
shows  the  former  are  under  weight  and  under  size.  They 
are  a  littje  later  in  reaching  puberty.  Even  this  type  sel- 
dom consults  the  physician  for  symptoms  due  to  the  disease, 
and  the  diagnosis  is  often  missed  when  they  do  come  under 
observation,  unless  hookworm  disease  is  suspected  and  an 
examination  of  feces  made.  Physicians  practicing  in  hook- 
worm districts  who  are  fully  aware  of  the  presence  of  the 
disease  in  their  practice,  and  who  have  diagnosed  and 
treated  severe  cases  of  the  disease,  usually  have  no  correct 
idea  of  the  prevalence  of  the  disease  of  this  and  the  very 
mild  types.  They  often  discuss  with  pride  their  having  dis- 
covered so  many  cases  of  hookworm  disease,  usually  rela- 
tively very  few,  in  their  practice,  when,  as  a  matter  of  fact, 
more  than  half  of  all  of  their  patients  have  the  disease, 
either  alone  or  associated  with  other  conditions.  In  one 
instance  we  know  of,  a  cotton  mill  physician  had  treated 
several  cases  of  severe  hookworm  disease  in  the  past  two 
years,  and  thought  himself  quite  expert  when  he  diagnosed 
two  cases  in  mill  employees.  About  that  time  the  manager 
read  in  a  newspaper  that  hookworm  disease  was  the  cause 
of  laziness,  and,  believing  that  all  of  his  employees  pre- 
sented this  one  of  the  symptoms,  he  summoned  the  physi- 
cian to  examine  the  sixty-two  boys  and  girls  for  hookworm 
disease.  He  decided,  after  looking  at  them  all,  that  the  two 
cases  already  diagnosed  were  all  there  were  in  the  mill,  and 
thought  it  unnecessary  to  examine  the  feces  of  any  more  of 
them.  They  decided,  however,  to  send  specimens  from  all 
of  them  for  examination,  regardless  of  the  doctor's  negative 
diagnosis,  and  of  the  sixty-two  there  were  found  fifty-six  in- 
fected. Many  of  them  were,  of  course,  very  mild  cases,  but 
that  not  a  few  were  more  pronounced  is  indicated  by  a 


SYlSrPTOMATOLOGY. 


125 


letter  from  the  manager  four  months  after  treatment  of  the 
fifty-six  cases,  in  which  he  says:  "The  time  keeper  had 
been  absent  nearly  three  months  on  account  of  sickness  in 
his  family,  and  on  his  return  he  found  that  many  of  the 
children  had  changed  so  much  he  often  had  to  ask  the 


Fig. 
about  7. 


j9.      Severe  hookworm  case;   subject  14  years  old,   but  appears   to  be 
(Photograph  furnished  by  Dr.  C.  W.  Stiles.) 


names  of  some  whom  he  had  previously  known  well.  The 
working  capacity  of  the  hands  has  been  increased  at  least 
25  percent,  and  I  feel  that  the  small  fee  I  paid  you  is  insig- 
nificant in  comparison  with  our  gain. ' ' 

We  may,  for  convenience,  recognize  another  type — the 


126  HOOKWORM  DISEASE. 

severe  type,  in  which  the  hemoglobin  ranges  from  60  down 
to  30  percent,  and  the  i^atient  is  too  weak  and  dyspneic  on 
exertion  to  be  overlooked.  He  is  pale,  anemic,  and,  if  not 
an  adult,  his  growth  is  interfered  with.  He  often  grows 
very  little  for  years,  and,  if  the  infection  is  kept  up,  the 
patient  may  be  no  larger  than  a  12  or  13-year  old  child  when 
he  is  actually  20.  He  will  continue  to  grow  until  he  is  26 
or  28  years  old  if  the  infection  lasts  a  long  time,  but  the 
size  attained  is  never  what  it  would  have  been  if  the  infec- 
tion had  never  occurred.  The  pubic  and  axillary  hair  ap- 
pears one,  two,  or  even  four  or  five  years  late,  and  the  beard 
does  not  start  until  the  patient  is  24  or  25  years  old.  We 
know  of  an  instance  in  which  there  were  two  deaths  in  a 
family  from  what  we  now  know  to  have  been  the  very 
severe  dropsical  form  of  hookworm  disease,  and  several 
other  boys  had  this  severe  type.  They  were  often  crippled 
with  ground  itch,  and  were  typical  anemic  dirt  eaters.  One 
of  the  boys  at  14  went  to  live  with  an  uncle  in  a  small  town, 
and  was  thus  removed  from  the  continued  reinfection  to 
which  the  other  four  were  exposed.  When  he  left  home  he 
looked  no  better  than  his  brothers,  but  at  the  age  of  20  he 
weighed  about  one  hundred  and  fifty  pounds  and  had  a 
pretty  heavy  beard.  He  sometimes  went  home  and  thence 
to  church  with  his  brothers,  two  of  them  older  than  himself, 
and  it  was  comical  to  see  them  together,  knowing  their  ages 
and  relation.  One  of  them  made  a  small  man  at  the  age 
of  about  27,  but  had  little  or  no  beard  at  about  30.  When 
about  35  he  had  grown  a  fairly  heavy  beard.  If  the  severe 
infection  occurs,  however,  after  the  patient  is  fully  grown 
and  the  beard  has  come  out,  the  latter  often  feels  and  looks 
dry  and  dead,  but  does  not  disappear.  In  this  type  in 
women  menstruation  is  delayed,  irregular,  scanty,  or  ab- 
sent. In  certain  hookworm  sections  in  this  country  this 
type  is  common. 


SYMPTOMATOLOGY. 


127 


Fig.  41  is  from  an  interesting  ease  of  this  kind,  re- 
ported from  Dr.  Dock's  clinic  in  the  Charity  Hospital, 
New  Orleans,  by  Dr.  I.  I.  Lemann.  The  subject,  22  3^ears 
old,  was  usually  taken  to  be  13  or  14.  The  bony  develop- 
ment corresponded  to  that  of  11 V2  years.  The  careful 
analysis  of  Dr.  Lemann  shows  that  the  dwarfing  process 
was  general.  "There  is  no  disproportion  between  the 
lengths  of  the  limbs  and  the  trunk;  no  undue  size  of  the  ex- 


Fig.    40.      Severe   hookworm    case;    subject    16    years    old.     Emaciation;    no 
edema. 

tremities  or  the  head."     The  height  at  the  time  was  139.5 
centimeters,  or  about  four  feet  eight  inches. 

We  may  recognize  a  severe  type  of  the  disease  in  which 
the  hemoglobin  ranges  from  30  down  to  8  or  10  percent,  and 
is  frequently  accompanied  by  albuminuria  and  dropsy.  The 
anemia,  pallor,  and  weakness  usually  incapacitate  patients 
for  any  kind  of  work,  and  when  dropsy  is  present  they  often 
have  to  remain  in  bed.     In  this  type  death  may  occur  from 


128 


HOOKWORM  DISEASE. 


the  hookworm  disease  alone,  whereas  in  the  previous  types 
death  does  not  occur,  except  as  a  result  of  some  intercurrent 


Fig-.  41.  Hookworm  .subject  22  years  old.  Three  hundred  hookworms  ex- 
pelled two  years  ago;  numerous  ova  now  (1909).  (Case  to  be  reported  by 
Dr.  I.  I.  Lemann,  1910.) 

disease.  This  type  of  hookworm  disease  is,  however,  a 
fruitful  source  of  death  by  lowering  the  patient's  vitality 
and  resistance  against  other  diseases  to  which  he  now  sue- 


SYMPTOMATOLOGY. 


129 


Climbs,  tliougli  uoriually  lie  would  have  recovered  from 
them.     There  are  relatively  very  few  cases  of  this  type  in 


Fig.  42.      Side  view  of  Fig.  41. 


the  United  States.  According  to  the  opinion  of  the  Porto 
Rico  Anemia  Commission,  about  30  percent  of  all  the  deaths 
in  the  island  are  due  to  this  type  of  the  disease. 


130 


HOOKWORM  DISEASE. 


This  arbitrary  division  of  the  disease  into  several  differ- 
ent types  is  nsefnl  mainly  to  enable  ns  to  convey  in  our  de- 


Fig.   43.     Rontgenogram   of  hand  of  hookworm   subject   shown   in  Fig.    41. 
(Negative  furnished  by  Dr.  A.  Granger,  New  Orleans.) 

scription  of  the  disease  a  more  definite  idea  or  meaning  for 
snch  terms  as  very  mild,  mild,  severe,  and  very  severe  cases. 
Each  type  must  merge  imperceptibly  into  the  other.    In- 


SYMPTOMATOLOGY. 


131 


....or^'^^§■    44.     Rontgenogram    of   hand   of   normal   man    19    years   old 
graph  furnished  by  Dr.  Thomas  Morgan  Rotch.) 


(Photo- 


132  HOOKWORM  DISEASE. 

asmuch  as  the  symptoms  and  results  of  the  disease  are  due 
chiefly,  if  not  wholly,  to  anemia,  we  believe  whatever  classi- 
fication is  necessary  should  be  based  on  the  amount  of 
hemoglobin  a  patient  has.  We  would  classify  cases  with 
over  80' percent  hemoglobin  as  very  mild;  those  with  80 
percent  to  60  percent,  mild;  those  with  60  percent  to 
30  percent,  severe;  and  those  with  less  than  30  percent, 
very  severe.  Ashford  and  King  distinguish  three  grades  of 
the  disease — slight,  moderate,  and  marked.  Their  "slight" 
cases  correspond  about  to  our  mild  cases,  their  "moderate" 
to  our  severe,  and  their  "marked"  cases  to  our  very  severe 
ones.  Their  summary  of  the  symptoms  under  each  head  is 
so  complete,  and  yet  brief,  that  we  quote  it  below  in  full. 
Up  to  this  writing  (1910),  theirs  is  the  only  very  large 
series  of  observations  and  statistics  on  hookworm  disease 
due  to  uncinaria  Americana. 

"Slight  cases. — Such  as  those  who  possess  little  or  no 
pallor,  or,  at  best,  show  but  an  indefinable,  dirty  yellow 
tinge  of  the  skin  in  whites  and  a  slight  pastiness  in  mulat- 
toes.  There  is  a  reduction  in  the  normal  amount  of  perspi- 
ration. The  appetite  is  apt  to  be  capricious.  Attacks  of 
gastralgia  are  felt  at  odd  times,  or  at  least  a  little  uneasi- 
ness in  the  epigastrium,  a  tendency  to  meteorism,  slight 
breathlessness  on  exertion,  occasional  palpitation  of  the 
heart,  dizziness,  headache,  lack  of  attention  to  details,  and 
a  little  dulling  of  the  mental  faculties.  The  muscles  are 
flabby,  and  weakness  and  indisposition  to  labor  exist.  The 
hemoglobin  of  such  persons  generally  lies  between  60  per- 
cent and  normal,  the  former  sometimes  in  spite  of  a  good 
color. 

"Moderate  cases. — These  form  the  usual  type  seen  in 
Porto  Rico,  although,  naturally,  marked  cases  predomi- 
nated among  those  applying  for  treatment.     Here  all  symp- 


SYMPTOMATOLOGY.  133 

toms  noted  under  slight  cases  are  more  prominent.  The 
pallor  is  definite,  the  mucous  membranes  are  paler  than 
normal,  the  skin  is  quite  dry,  and  sweating  is  rare.  Appe- 
tite may  be  exaggerated  to  the  point  of  bulimia,  or  even 
perverted  to  geophagy.  Nausea  is  frequent,  and  vomiting 
may  occur  at  times.  The  tongue  is  coated,  and  often  flabby 
and  enlarged.  There  may  be  some  tenderness  of  the  epi- 
gastrium and  abdomen,  with  spontaneous  pain  and  heavi- 
ness. Breathlessness  is  much  more  easily  elicited.  Palpi- 
tation of  the  heart  is  frequent  and  severe,  and  not  always 
relative  to  exertion.  The  pulse  is  more  rapid,  and  is  liable 
to  be  weak  and  compressible.  There  is  often  a  hemic  mur- 
mur of  the  heart  and  a  little  hypertrophy.  The  pulsation 
of  the  vessels  of  the  neck  is  noticeable.  There  is  much  pain 
in  the  sternum  and  chest,  with  a  feeling  of  weakness  of 
knees  and  legs.  The  patient  feels  sick.  There  is  much  diz- 
ziness, especially  on  sudden  changes  of  position,  noise  in 
the  ears,  and  frequent  headache.  The  mental  condition  is 
decidedly  depressed,  and  the  patient  is  quite  passive  to  his 
surroundings  and  appears  stupid.  Sometimes  the  patellar 
reflex  is  exaggerated,  but  more  often  it  is  diminished. 
There  is  susceptibility  to  cold,  and  tingling  of  the  feet, 
which  frequently  'go  to  sleep.'  The  muscles  are  flabby  and 
a  little  painful.  Joint  pains  are  so  common  that  a  diag- 
nosis of  rheumatism  is  often  made.  Work  is  undertaken 
with  great  effort.  The  hemoglobin  is  apt  to  be  between 
30  and  60  percent. 

"Marked  cases. — Here  the  patient  has  arrived  at  that 
stage  where  fatal  termination  may  occur  at  any  time.  The 
pallor  is  very  extreme.  Edema  of  the  feet  and  ankles 
alone,  or  sometimes  extreme  anasarca,  is  seen.  The  diges- 
tive disturbances  have  changed  in  character,  and  appetite 
is  often  nil — often  enormous.  Some  of  the  worst  forms  of 
geophagy  are  here  seen.     Nausea  and  vomiting  are  fre- 


134  HOOKWORM  DISEASE. 

qiient.  Ascites  is  liable  to  appear  and  become  alarming. 
Diarrhea  may  alternate  Avitli  constipation.  There  is  dis- 
tressing dyspnea  on  the  slightest  movement,  and  sometimes 
when  the  patient  is  perfectly  quiet;  severe  palpitation  of 
the  hear^;  precordial  pain;  rapid,  weak,  compressible 
pulse,  and  often  dilatation  of  the  heart.  Marked  pulsation 
of  the  vessels  of  the  neck  and  of  the  base  of  the  neck  may 
be  noticed  at  some  distance.  There  is  often  pulsation  of 
the  great  veins,  with  bruit-de-diable  of  the  jugulars.  Diz- 
ziness and  tinnitus  aurium  are  extreme.  There  is  much 
headache  and  insomnia.  The  patellar  reflex  is  abolished. 
In  men,  impotence  is  an  almost  invariable  symptom,  and 
amenorrhea  in  women.  The  intellect  is  much  dulled;  men- 
tal processes  are  slow,  and  the  patient  seems  confused  and 
stupid.  The  facial  expression  is  melancholic  and  anxious. 
Paresthesias  become  very  marked.  There  is  a  tendency  to 
dilatation  of  the  pupil,  and  blurred  vision  exists.  The  urine 
has  a  low  specific  gravity,  is  abundant  in  quantity,  and 
usually  contains  no  albumin.  The  muscles  are  flabby,  sore, 
and  painful.  Extreme  weakness,  even  to  the  simulation  of 
paralysis,  is  observed  and  the  patient  is  incapacitated  for 
labor.  There  may  be  irregular  fever,  with  intervals  of  sub- 
normal temperature." 

Acute  hookworm  disease  may  occur  without  previous  in- 
fection, or  an  acute  attack  may  supervene  on  a  chronic  in- 
fection. These  acute  attacks  occur  in  the  spring  and  sum- 
mer, and  their  symptoms  will  vary  with  the  intensity  of  the 
infection.  If  sufficient  infection  occurs,  there  will  be  di- 
gestive disturbances,  epigastric  pains,  rapid  anemia,  and 
generally  elevations  of  temperature  as  high  as  101°  or 
101  1/2°  F.  One  difference  to  be  noted  between  acute  and 
chronic  eases  is  that  in  the  acute  the  patient  looks  waxy 
white,  with  severe  anemia,  whereas  in  chronic  cases,  with 


SYMPTOMATOLOGY.  135 

the  same  amount  of  anemia,  there  is  a  more  yellow  tinge 
(^'tallow  faced")  to  the  skin,  due  to  more  or  less  pigmenta- 
tion. Children  with  acute  hookworm  disease  have  not  the 
"pot  belly"  present  in  so  many  of  the  chronic  severe  cases. 

Symptoms  on  the  Part  of  Certain  Tissues  and  Organs. 

Blood. — Anemia  is  the  most  constant  symptom  of  hook- 
worm disease,  and  determines  the  severity  in  a  given  case. 
It  may  vary  from  the  slightest  degree  below  normal  to  a 
sufficient  degree  to  label  the  patient.  The  type  is  almost 
always  that  of  a  secondary  anemia  or  chlorosis.  The  hemo- 
globin ranges  from  8  percent  up,  according  to  the  severity 
of  the  case.  Most  of  the  cases  in  this  country  range  from 
normal  down  to  40  or  50  percent.  We  have  records  of  the 
hemoglobin  estimation  in  four  hundred  and  thirty-two 
cases  occurring  chiefly  in  Mississippi  and  Louisiana.  The 
lowest  is  15  percent,  and  several  records  of  very  mild  hook- 
worm carriers  are  95  and  even  100  percent.  The  average 
for  all  the  cases  is  67  2/3  percent.  It  must  be  understood, 
however,  that  the  number  includes  a  great  many  very  mild 
cases.  Ashford  and  King  found  in  five  hundred  and  seven- 
ty-nine cases  on  entrance  a  hemoglobin  percentage  of  9  to 
101  percent — average,  43.09  percent.  Soon  after  infection 
the  hemoglobin  falls  much  faster  than  the  number  of  red 
cells.  In  fact,  it  may  even  reach  a  pretty  low  figure  before 
they  begin  to  decline. 

The  number  of  red  cells  is  reduced  slowly  as  the  anemia 
develops,  but  most  severe  cases  have  3,000,000  to  5,000,000 
cells.  The  average  count  in  sixty  cases  reported  by  Ashford 
and  Kingi/was  2,406,416.  We  have  made  a  blood  count  in 
forty-two  cases  and  obtained  an  average  of  3,459,246.  Forty 
university  students  found  to  be  hookworm  carriers  gave  an 
average  of  5,246,322.     The  cells  are  pale,  and  stippling  is 


136  HOOKWORM  DISEASE. 

generally  present,  but  to  no  great  extent.  Normoblasts  are 
generally  present,  but  megaloblasts  are  rare.  Poikilocy- 
tosis  and  polycliromatopliilia  occur  as  the  anemia  increases, 
but  are  never  as  pronounced  as  in  pernicious  anemia. 
Anisocytosis  is  present,  as  in  all  the  severe  anemias. 

Though  this  secondary  type  of  anemia,  with  relatively 
low  hemoglobin  percentage,  giving  rise  to  low  color  indices, 
is  what  is  generally  seen,  there  occur  a  few  cases  in  which 
the  number  of  red  cells  is  reduced  as  much  as  or  more  than 
the  hemoglobin  percentage,  giving  rise  to  color  indices 
sometimes  above  1.0.  We  have  seen  an  index  of  1.35,  count- 
ing 5,000,000  red  cells  normal  and  estimating  hemoglobin 
with  the  von  Fleischl  apparatus.  Patients  with  this  type 
of  anemia  are  the  most  resistant  to  treatment,  and  often  re- 
main anemic  as  long  as  even  very  small  numbers  of  worms 
remain.  In  fact,  they  sometimes  have  only  small  numbers 
before  any  treatment  is  instituted.  They  recover  very 
slowly,  but  usually  finally  get  entirely  well  after  expulsion 
of  all  their  worms. 

The  leucocytes  are  not  generall}^  increased.  Counts  of 
13,000  or  14,000  occasionally  occur.  We  saw  a  case  with  a 
history  of  recent  severe  ground  itch  in  whom  the  leucocyte 
count  went  as  high  as  19,400.  The  patient  had  fever  some- 
times as  high  as  101°,  and  no  cause  could  be  found,  except 
the  hookworm  disease.  We  have  records  of  the  leucocyte 
count  in  sixty-eight  cases  of  hookworm  disease  of  various 
degrees,  the  average  of  which  is  8,746. 

The  differential  leucocyte  count  usually  shows  nothing 
abnormal,  except  as  regards  the  eosinophiles.  These  cells 
vary  in  number  considerably,  but  without  following  any 
known  fixed  law.  Generally,  their  percentage  is  increased. 
Leichtenstern  saw  a  remarkable  case  with  72  percent.  The 
highest  we  have  seen  was  34  percent.  Fifteen  to  25  percent 
are  ordinary  counts  for  our  severe  cases.     Though  most 


SYMPTOMATOLOGY.  137 

cases  have  counts  above  normal,  a  few  have  a  normal  num- 
ber. The  eosinophile  percentage  often  is  not  in  proportion 
to  the  severity  of  the  disease.  In  very  severe  cases  the 
count  is  low — maybe  within  normal  limits — and  rises  after 
treatment  for  some  time,  and  then  again  comes  down  slow- 
ly. Very  few  patients  have  eosinophilia  when  they  die. 
The  eosinophilia  seems  to  depend  on  other  factors  than  the 
number  of  worms.  While  expulsion  of  all  worms  is  fol- 
lowed in  certain  instances  by  a  normal  eosinophile  count 
even  before  the  hemoglobin  has  reached  normal,  in  many 
it  is  several  months  before  normal  counts  are  obtained. 
The  eosinophile  counts  in  five  hundred  and  thirty-two  cases 
of  all  grades  seen  by  us  give  an  average  of  5.7  percent,  but 
nearly  half  of  them  were  of  the  very  mild  type,  nearly  all  of 
which  had  only  slight  increase  or  none  at  all.  It  is  to  be 
remembered  that  eosinophilia  occurs  in  a  variety  of  other 
diseases  besides  hookworm  disease,  which  detracts  from 
its  diagnostic  value.  It  is,  however,  present  sufficiently  fre- 
quently in  this  disease  to  indicate  an  examination  of  the 
feces  whenever  it  is  found.  When,  however,  no  increase  is 
found,  hookworm  disease  can  not  be  ruled  out.  An  increas- 
ing eosinophilia  after  treatment  would  be  of  favorable  prog- 
nostic value. 

Joint  pains. — The  observation  of  Leichtenstern  that  joint 
pains  and  pains  in  the  bones  occur  is  confirmed  by  Ashford 
and  King,  who  say  that  pain,  especially  in  the  sternum,  is 
an  almost  universal  symptom. 

Skin — Ground  itch. — Synonyms:  Water  itch,  water  blis- 
ter, water  pox,  toe  itch,  dew  poison,  dew  crack,  mud  itch, 
''new  sump  bunches"  of  Cornish  miners,  sore  feet  of  coo- 
lies, "pani-ghao,"  "mazomorro"  (Porto  Eico). 

Ground  itch  varies  very  much  in  its  symptoms  with  the 
intensity  of  the  infection,  the  location,  and  the  secondary 
infection.    It  is  now  certain  that  it  is  caused  by  the  hook- 


138  HOOKWORM  DISEASE. 

worm  larvae,  which  penetrate  the  skin.  Claude  A.  Smith 
produced  symptoms  resembling  ground  itch  by  the  applica- 
tion of  an  alcoholic  extract  of  the  larvae  to  the  arm  of  a  pa- 
tient. This  experimental  ground  itch  resembled  that 
caused  by  applying  the  larvae  to  the  skin.  The  amount  of 
infection  may  vary,  of  course,  from  one  microscopic  larva 
to  several  thousand,  and  would  give  rise  to  quite  variable 
symptoms. 

Ground  itch  is  a  collective  term,  and,  although  in  hook- 
worm countries  it  is  usually  due  to  the  larvae  of  those 
worms,  conditions  clinically  similar,  at  least  to  inexperi- 
enced persons,  may  be  due  to  other  causes.  Van  Durme 
and  Looss  have  shown  that  strongyloides  larvae  can  pene- 
trate the  skin  just  as  hookworm  larvae  do,  and  our  associate. 
Dr.  J.  C.  Gage,  has  confirmed  this.  From  the  experiments 
with  various  species  of  hookworm  larvae  in  different  ani- 
mals it  is  probable  that  various  nematode  larvae  can  pene- 
trate the  skin  and  set  up  local  lesions,  but  not  develop  in 
the  body.  So  the  larvae  of  the  hookworms  of  dogs  and 
other  animals  may  possibly  cause  ground  itch.  Similar 
lesions  may  be  caused  by  ticks,  harvest  bugs,  sand  fleas, 
fly  larvae,  and  other  insects. 

The  disease  is  most  likely  to  be  located  on  the  feet,  but 
the  hands  maj  be  affected,  as  in  gardeners,  miners,  and 
others  whose  occupation  leads  them  to  handle  infected  earth 
and  mud,  or  in  children  from  ]3laying  in  infected  sand  and 
mud. 

In  rural  districts,  where  hookworm  disease  is  most  preva- 
lent, little  children  often  wear  only  one  dress  or  shirt,  or  an 
apron.  Sometimes  children  in  their  "shirt  tail"  sit  down 
on  infected  mud  and  sand,  and  thus  get  infected  on  the  but- 
tocks. By  far  the  most  common  location  is  the  feet,  and 
between  and  beneath  the  toes.  This  is  because  infected 
mud  is  squeezed  in  between  them,  and  is  more  likely  to  re- 


SYMPTOMATOI^OGY.  139 

main  until  the  larvsB  have  time  to  penetrate  the  skin.  The 
lesion  is  also  often  located  around  the  edge  of  the  soles  at 
the  juncture  of  the  thick  and  thin  skin.  It  is  not  so  com- 
mon on  the  dorsum  of  the  feet,  except  just  above  the  toes. 
The  soles  are  not  so  much  affected  as  other  parts.  The 
inner  side  of  the  sole,  where  there  is  little  pressure,  is  a 
favorite  location.  All  of  these  places,  it  will  be  noted,  are 
those  most  likely  to  get  mud  on  them  and  have  it  remain 
if  the  child  steps  in  it.  We  have  seen  the  eruption  involve 
the  legs  from  wading  in  infected  water  on  the  farm,  aud  it 
sometimes  comes  around  the  ankles  when  muddy  water 
gets  over  the  shoetops.  A  few  minutes  after  infected 
mud  is  applied,  stinging  of  the  skin  occurs.  This  occurs 
so  promptly  that  little  boys  often  learn  what  kind  of 
places  they  get  ground  itch  from  and  avoid  them.  With- 
in a  few  hours  redness,  stinging,  and  itching  put  the 
victim  to  rubbing  and  scratching.  Many  a  country  boy 
has  cried  and  spent  restless  nights  with  his  ground  itch. 
The  cry  then  increases,  there  occurs  more  or  less  swelling, 
and  the  itching  is  more  intense.  The  desire  to  scratch  is 
irresistible  and  the  satisfaction  of  scratching  partially  re- 
pays for  the  unpleasantness  of  the  disease.  In  twenty-four 
to  thirty-six  hours  small  pinhead  sized  vesicles  appear, 
which,  according  to  the  amount  of  infection,  may  not  be 
numerous,  or  they  soon  become  confluent.  The  vesicles  are 
common  on  the  inner  surfaces  of  the  toes,  where  they  are  in 
contact.  -  The  macules  which  precede  the  vesicles  where 
the  infection  is  very  slight  are  larger  and  more  painful,  and 
itch  worse  on  the  soles  and  thick  skin.  The  vesicles  are 
more  likely  to  become  confluent  between  and  in  the  folds 
beneath  the  toes,  which  results  in  loosening  considerable 
skin.  It  is  tougher  here,  and  usually  comes  off  in  a  thick, 
heavy  layer  after  a  week  or  two,  leaving  the  tender  skin  be- 
neath.    Scratching  and  rubbing  often  break  the  small  vesi- 


140  HOOKWORM  DISEASE. 

cles,  and  scabbing  occurs,  but  usually  slowly  on  account  of 
the  fact  that  the  itching  continues  so  intense  for  several 
days  that  scratching  can  hardly  be  avoided.  In  twenty- 
four  to  forty-eight  hours  the  eruption  becomes  pustular,  due, 
no  doubt,  to  secondary  infection.  This  occurs  much  more  in 
certain  individuals  and  at  certain  times  than  others,  doubt- 
less due  to  the  conditions  governing  pyogenic  infection  in 
general.  Examination  of  the  pus  usually  shows  staphy- 
lococci. Bentley  found  an  ankylostoma  larva  in  a  vesicle. 
The  pustules  are  frequently  ruptured,  as  are  the  vesicles, 
and  leave  a  raw  surface,  with  rather  profuse  sticky  exuda- 
tion. This  exudate  sticks  the  socks  or  bandages  to  the  foot, 
and  a  part  of  the  undressing  performance  every  night  with 
little  boys  so  affected  is  the  necessary  soaking  of  the  feet  to 
loosen  the  adherent  dressing.  Deep  ulcers  do  not  occur,  ex- 
cept in  the  folds  beneath  and  between  the  toes,  where  they 
may  be  deep  and  last  several  weeks.  Beneath  the  toes  the 
deep  ulcers  or  cracks  are  kept  up  by  the  bending  of  the 
toes,  and  often  remain  after  all  other  traces  of  the  disease 
have  disappeared.  The  toes  are  often  glued  tightly  to- 
gether by  the  sticky  exudate,  and  where  it  remains  moist 
the  skin  is  white  and  often  loosened.  In  cases  where 
the  vesicles  are  not  ruptured,  or  where  they  are  rubbed 
off,  they  dry  up  in  about  five  days,  and  in  about  eight 
or  ten  days  exfoliation  and  healing  are  complete.  Little 
evidence  of  the  lesion  now  remains,  except  between  and 
beneath  the  toes,  where  the  skin  is  so  thick  that  it  is  not 
shed  so  rapidly.  Patients  often  trim  this  off,  and,  unless 
the  ulceration  is  especially  deep,  or  deep  fissures  occur,  the 
healing  is  not  delayed  much  beyond  that  of  other  parts. 

In  very  intense  infections,  as  in  Claude  A.  Smith's  experi- 
mental case,  great  swelling  occurs  on  the  second  and  third 
days.  The  lymphatic  glands  draining  the  part  are  often 
swollen  and  tender,     Looss  has  noted  red  lines  running  up 


SYMPTOMATOLOGY.  141 

tlie  limb — probably  lymphangitis.  There  is  local  fever  dur- 
ing the  height  of  the  inflammation,  but  no  systemic  eleva- 
tion of  temperature,  except  in  very  severe  cases.  When 
the  disease  is  located  on  the  feet,  the  diagnosis  is  usually 
easy.  In  fact,  nearly  any  country  boy,  or  mother,  or  father 
in  a  hookworm  country  knows  what  ground  itch  is  usually 
from  experience,  and  recognizes  it  on  sight.  When  located 
on  other  parts  of  the  body,  the  differential  diagnosis  often 
can  not  be  made  from  other  diseases  causing  very  similar 
lesions.  The  history  of  exposure  and  the  course  of  the  dis- 
ease help  to  settle  the  diagnosis.  The  prompt  occurrence  of 
eosinophilia  in  most  cases  helps  to  strengthen  the  diagnosis. 
This  is  present  in  four  to  five  days  after  infection. 

The  color  of  the  skin  in  chronic  hookworm  disease  is  usu- 
ally pale,  with  a  yellow  tinge.  This  gives  rise  to  the  fre- 
quent description,  "tallow  faced."  In  acute  cases,  where 
the  anemia  rapidly  develops,  the  patient  is  paler  and  whiter. 
Exposure  to  the  sun  finally  hides  more  or  less  of  the 
anemia.  The  pallor  is  generally  in  proportion  to  the 
anemia,  but  this  is  not  always  a  true  guide.  Patients  with 
60  percent  hemoglobin  may  look  better  than  others  with 
90  percent.  In  negroes  the  skin  becomes  gray  or  ashen 
from  severe  anemia. 

The  skin  of  severe  hookworm  disease  is  often  wrinkled, 
so  as  to  give  the  patient  the  appearance  of  being  much  older 
than  he  is.  This  usually  fills  out  again  after  proper  treat- 
ment. 

Liver. — No  change  in  this  organ  or  its  functions  can  be 
made  out  clinically. 

Spleen. — The  spleen  is  unchanged,  except  in  cases  com- 
plicated with  such  diseases  as  alter  it,  as  malaria,  leu- 
kemia, splenic  anemia,  etc. 

Respiratory  system. — During  the  few  days  (first  ten) 
after  an  attack  of  ground  itch,  if  the  infection  is  very  con- 


142  HOOKWORM  DISEASE. 

siderable,  there  may  be  cough,  bronchitis,  and  sore  throat. 
Ex]3erimentally  there  occur  hemorrhages  into  the  lung 
tissue,  and  it  is  not  impossible  that  there  may  be  secondary 
bacterial  infection  and  a  condition  resembling  pneumonia 
develop,  [^he  possibilities  are  illustrated  by  an  experiment 
done  by  Ashford  and  King.  They  applied  a  culture  of  un- 
cinaria  Americana  larvae  to  the  back  of  a  four-day  old 
guinea  pig.  In  three  days  the  animal  died.  Autopsy 
showed  one  lung  solid  with  blood  and  the  other  containing 
several  hemorrhagic  spots  or  blood  cysts,  many  of  which 
contained  uncinaria  larvae.  Such  instances  would,  of  course, 
not  be  diagnosed  as  hookworm  disease,  but  we  believe  the 
possibilities  are  sufficiently  great  to  warrant  consideration 
in  cases  of  ground  itch.  Examinations  of  the  sputum  might 
reveal  larvae.  If  the  blood  were  examined  at  such  times  by 
the  method  of  Staubli — dissolving  in  3-percent  acetic  acid 
and  centrifugating — the  larvae  might  be  recovered  from  it, 
as  have  trichinae  by  Herrick  and  Janeway.  It  is  not  clear 
from  Staubli 's  (1908)  article  that  he  really  found  hook- 
worm larvae. 

Dyspnea. — On  exertion,  dyspnea  is  one  of  the  most  promi- 
nent symptoms  in  cases  with  hemoglobin  below  50  or  60  per- 
cent. It  often  has  existed  so  long  that  the  patient  looks  on 
it  as  normal  for  him  and  as  a  necessary  part  of  his  life. 
This  is  one  of  the  symptoms  that  reduces  the  patients '  work- 
ing capacity,  and  contributes  to  the  reputation  they  often 
have  of  being  lazy.  Edema  of  the  lungs  and  hydrothorax 
are  likely  to  be  present  in  the  severe  cases,  with  general 
edema.  Ashford  and  King  mention  a  ''dry  cough"  in 
severe  cases.  This  may  be  due  to  edema  of  the  lungs  or 
hydrothorax. 

Circulatory  system. — Pulsation  of  the  neck  veins,  mucli 
increased  by  exertion,  is  frequently  present  in  all  severe 
cases  of  hookworm  disease.     The  heart,  on  inspection  in 


SYMPTOMATOLOGY.  143 

severe  cases,  shows  a  wide  area  of  cardiac  impulse,  such  as 
is  seen  in  dilatation  from  any  other  cause.  Pulsation  in  the 
epigastrium  is  a  prominent  symptom,  and  often  this  and  the 
extensive  cardiac  impulse  attract  the  attention  of  the 
patient.  These  symptoms  are  very  much  increased  by  ex- 
ertion, as  are  also  the  pulsations  in  the  neck.  On  palpation 
the  heaving,  easily  seen  impulses  are  found  to  be  weak.  On 
percussion  the  area  of  cardiac  dullness  is  increased  to  the 
left,  but  not  much  downward.  There  often  is  right-sided 
enlargement.  Relative  cardiac  dullness  in  many  cases  ex- 
tends to  the  left  of  the  nipple  line  and  far  to  the  right  of 
the  sternum. 

Auscultation  generally  reveals,  in  cases  with  hemoglobin 
below  50  or  60  percent,  a  hemic  murmur,  best  heard  in  the 
left  third  interspace,  but  frequently  heard  all  over  and 
sometimes  beyond  the  cardiac  area. 

The  pulse  in  mild  cases  is  little  changed,  but  in  the 
severer  ones  is  weak  and  dicrotic,  irregular,  and  compress- 
ible in  the  severest  cases,  and  in  the  latter  it  is  rapid, 
thready,  and  intermittent.  The  frequency  increases  with 
the  severity  of  the  disease,  but  often  is  marked  in  mild 
cases.  The  following  is  the  pulse  rate  of  twenty  selected 
uncomplicated  representative  cases  from  Mississippi  and 
Louisiana,  between  the  ages  of  15  and  25,  and  we  believe 
represents  the  average  in  hookworm  patients  in  this  country 
who  are  sick  enough  to  consult  a  physician:  84,  84,  89,  96, 
98,  99,  110,  113,  114,  114,  124,  128,  128,  129,  132,  133,  141, 
142,  146,  and  148.  The  average  of  the  twenty  cases  is  117.6. 
The  blood  pressure  averages  below  normal,  and  usually  goes 
lower  as  the  severity  of  the  disease  increases.  In  two  of 
our  cases  albuminuria  and  nephritis  were  present,  and  the 
blood  pressure  by  the  Riva  Roci  instrument,  with  two-and- 
one-half-inch  band,  was  145  and  163.  Twelve  cases  of 
average  uncomplicated  hookworm  disease  over  15  years  old 


144  HOOKWOEM  DISEASE. 

seen  by  us  had  an  average  blood  pressure  by  this  instru- 
ment and  in  the  sitting  posture  of  110.  They  were  in  de- 
tail, 89,  93,  94,  99, 104, 106, 109, 117, 124, 126, 127,  and  132. 

Dig'estive  system. — The  symptoms  relative  to  the  diges- 
tive systeifL  will  necessarily  vary  much  on  account  of  the 
very  great  variation  of  the  amount  of  the  infection.  In 
severe  cases  the  tongue  is  pale,  coated,  and  often  indented, 
and  occasionally  shows  purple  lines  on  either  side  of  the 
median  line,  probably  due  to  dilation  of  the  veins.  Pig- 
mented spots  on  the  tongue  have  been  noted  in  dark-skinned 
races.  It  is  possible  that  these  may  be  caused  by  larvae 
penetrating  the  mucous  membrane  after  they  have  come  up 
from  the  lungs.  The  shedding  of  the  first  teeth  and  erup- 
tion of  the  permanent  set  is  delayed  sometimes  one,  two,  and 
three  years,  according  to  the  severity  and  duration  of  the 
disease.  The  teeth  keep  up,  however,  pretty  well  with  the 
development  of  other  parts  of  the  anatomy. 

Following  a  severe  attack  of  ground  itch,  sore  throat 
usually  occurs  in  a  few  days.  Claude  A.  Smith  noticed  this 
in  one  of  his  experimental  cases  in  eight  days.  After  this 
the  patient  begins  to  complain  of  pain,  uneasiness  and  dis- 
comfort in  the  epigastrium,  due,  no  doubt,  to  the  trauma- 
tism and  irritation  of  the  gastric  and  intestinal  mucosa. 
The  young  larvsB  penetrate  the  mucous  membrane  and  pro- 
duce considerable  blood-cyst  formation.  If  any  difference, 
the  right  upper  quadrant  of  the  abdomen  is  the  seat  of 
most  of  the  trouble.  There  may  be  tenderness,  especially 
in  this  region  and  in  the  epigastrium.  Lutz  believed  this 
was  definitely  connected  with  hookworm  infection  of  the  in- 
testine. We  have  been  impressed  with  the  relation  between 
epigastric  uneasiness  and  pain  and  hookworm  disease.  Dr. 
J.  B.  Elliott,  Sr.,  formerly  professor  of  theory  and  prac- 
tice of  medicine  in  Tulane  University,  was  one  of  the  first 
in  this  country  to  recognize  the  influence  of  mild  hookworm 


SYMPTOMATOLOGY.  145 

infection  in  producing  epigastric  pain  and  discomfort,  usu- 
ally of  a  vague  and  indefinite  description.  Several  years 
ago  lie  learned  that  a  few  such  cases  in  which  he  could  find 
no  explanation  for  the  symptoms  were  hookworm  carriers. 
Often  they  had  very  few  worms.  He  was  in  the  habit  of 
having  them  examined,  and  the  accuracy  with  which  he 
recognized  these  cases  was  in  keeping  with  the  character- 
istic keenness  of  which  he  was  known  to  be  possessed  by 
all  who  had  the  good  fortune  to  know  him. 

The  following  cases,  reported  b}-  one  of  us  (Bass,  1909), 
illustrate  this  point: 

Case  1. — J.  B.,  aged  39,  male,  white,  merchant,  was  well 
develoj^ed  and  looked  fairly  well;  had  never  had  ground 
itch;  lived  in  town.  He  had  had  vague  pains  in  the  right 
side  of  abdomen  as  long  as  he  could  remember;  said  he  was 
nervous  and  had  ' '  indigestion. ' '  Pains  were  not  related  to 
the  time  of  eating.  Physical  examination  failed  to  reveal 
anything  abnormal.  There  were  a  few  eggs  in  the  stools; 
fourteen  worms  were  recovered.  The  patient  recovered  en- 
tirely and  gained  nine  pounds  in  nine  weeks. 

Case  2. — L.,  aged  61,  white,  farmer's  wife,  had  had  no 
ground  itch.  The  negroes  on  the  plantation  had  it.  The 
patient  had  had  pains  in  the  right  side  and  uneasiness  in 
the  abdomen  for  the  past  six  years,  not  related  to  meals; 
tenderness  was  not  present.  Physical  examination  showed 
nothing  abnormal.  There  were  a  few  eggs  in  the  stools;  no 
anemia.  The  patient  recovered  on  treatment  with  thymol. 
Eight  months  later  she  was  still  well. 

Case  3. — Paul  H.,  aged  42,  male,  white,  lawyer,  com- 
plained of  indigestion  and  frequent  headaches.  He  had 
tenderness  in  the  right  side  of  the  abdomen.  There  were  a 
few  eggs  in  the  stools.  The  patient  was  relieved  of  indiges- 
tion and  headaches  after  the  first  course  of  thymol. 

Ashford  and  King  say  that  epigastric  pain  and  tenderness 


146  HOOKWORM  DISEASE. 

are  the  most  constant,  most  suggestive,  and  most  clearly 
marked  of  all  the  symptoms  of  the  digestive  tract.  We  do 
not  believe  that  this  is  true  of  the  type  of  the  disease  most 
prevalent  in  this  country,  but  we  have  noted  it  in  many  of 
our  cases.  We  are  also  quite  confident  that  it  is  a  more 
common  Symptom  in  adults  than  in  children,  and,  further, 
that  a  small  number  of  worms  may  produce  it.  If  such  dis- 
comfort and  mild  eiDigastric  pain  were  not  so  often  observed 
in  other  conditions,  it  would  be  a  more  serviceable  diag- 
nostic sjTnptom. 

The  appetite  is  increased  in  most  mild  and  medium  severe 
cases,  but  anorexia  is  frequent  in  the  severest  cases.  Per- 
versions of  appetite  are  common,  even  in  mild  cases.  All 
sorts  of  unnatural  things  are  eaten,  such  as  earth,  paper, 
slate  pencils,  lead  pencils,  coffee  ''grounds,"  ashes,  feath- 
ers, hair,  charcoal,  unripe  fruit,  etc.  We  know  of  a  woman 
with  hookworms  and  a  history  of  ground  itch  who  de- 
veloped such  a  craving  for  laundry  starch  that  she  ate  a 
pound  and  a  half  a  day.  After  keeping  that  up  for  some 
months  she  showed  symptoms  of  pellagra.  (Case  to  be  re- 
ported by  Dr.  Bass.)  Many  have  an  abnormal  appetite 
for  pickles,  lemons,  salt,  etc.,  and  resin  chewing  is  common 
among  those  living  in  the  "piney  woods"  section.  Many 
chew  hickory  or  other  bitter  bark.  Butterworth's  case  of 
hairball  in  the  stomach,  already  referred  to,  illustrates  the 
extremes  to  which  this  unnatural  appetite  may  go.  Dirt 
or  clay  eating  is  common,  and  the  worst  cases  in  an  in- 
fected locality  are  called  by  the  natives  "dirt  eaters"  or 
"clay  eaters."  The  anemia  is  supx)osed  to  be  due  to  dirt 
or  "trash"  eating,  and  parents  often  accuse  their  children, 
and  often  whip  them  in  spite  of  their  denial.  They  think 
the  anemia  is  sufficient  evidence  of  their  guilt. 

With  the  laity  in  hookworm  sections  and  others  the  belief 
is  pretty  common  that  eating  dirt  and  "trash,"  including 


SYMPTOMATOLOGY.  147 

various  kinds  of  candy  and  sweets,  and  unripe  or  spoiled 
fruit,  is  a  source  of  worms,  and  hookworm  families  are  gen- 
erally believed  to  be  "wormy,"  usually  meaning  they  have 
ascaris  infection. 

We  recall  an  instance  of  an  anemic  family,  due,  as  we  now 
know,  to  hookworm  disease,  in  which  many  different  reme- 
dies were  tried  to  break  the  children  from  eating  dirt  from 
the  clay  of  the  stick-and-dirt  chimney.  One  of  the  remedies 
tried  was  to  sprinkle  urine  on  the  chimney,  but  the  final  suc- 
cessful one,  so  far  as  that  chinmey  was  concerned,  was  rub- 
bing over  the  chimney  in  the  presence  of  the  children  a 
large  rattlesnake  that  had  been  killed  on  the  place.  The 
fear  of  snakes  was  sufficient  to  cure  them.  These  children 
were  among  the  most  inordinate  resin  chewers,  and  finally 
all  took  to  chewing  tobacco.  Chewing  tobacco  is  encour- 
aged by  this  unnatural  appetite,  and  we  believe  this  partly 
explains  the  very  extensive  use  of  the  weed  among  hook- 
worm people.  Boys  who  do  not  grow  well  are  often  advised 
by  their  physician  or  some  one  else  to  begin  chewing  to- 
bacco. They  do  often  begin  to  grow  at  this  time,  and  we 
have  heard  many  a  man  or  boy  say  he  never  took  a  start  to 
grow  until  he  began  to  chew  tobacco.  There  is  no  constant 
beneficial  result,  for  we  have  seen  many  of  these  tobacco 
chewers  who  had  practiced  the  habit  for  many  years 
and  still  had  not  "taken  a  start  to  grow."  The  reason 
many  of  them  begin  to  grow  after  they  begin  chewing 
tobacco  is,  no  doubt,  that  many  of  them  at  about  the  same 
time  begin  to  wear  shoes  or  otherwise  reduce  reinfection. 
It  may,  however,  be  possible  that  the  tobacco  juice  swal- 
lowed kills  or  injures  the  worms.  It  has  been  our  observa- 
tion that  when  dirt  is  eaten  in  a  country  having  red  clay  soil, 
this  is  generally  selected,  and  children  often  get  the  habit  of 
picking  and  eating  from  the  stick-and-dirt  chimneys  used 
by  the  poorer  class.     They  seem  to  prefer  the  very  dry  clay. 


148  HOOKWOEM  DISEASE. 

and  we  knew  one  negro  woman  who  would  bake  lier  clay  in 
the  stove.  She  often  made  it  up  like  bread  and  baked 
several  days'  supply  at  a  time.  Half  an  ounce  or  an  ounce 
at  a  time  was  often  used.  She  liked  to  put  a  small 
piece  in  her  mouth  and  suck  on  it  for  several  minutes  at  a 
time.  When  asked  why  she  ate  it  she  said,  "I  just  craves 
it."  Others  pick  up  little  soft  pebbles  and  suck  on  them. 
In  one  instance  a  16-year  old  anemic-looking  boy,  whom  we 
would  now  recognize  as  a  hookworm  patient,  became  very 
ill,  and  was  given  a  glycerine  enema.  He  expelled  in  a  few 
minutes  several  ounces,  consisting  chiefly  of  pebbles,  which 
he  then  admitted  he  had  been  eating  for  over  two  years. 
If  earth  were  the  only  substance  eaten,  the  opinion  that  this 
symptom  is  due  to  an  instinctive  effort  to  supply  iron  and 
manganese  with  which  to  build  up  hemoglobin  might  be 
admitted  to  have  some  basis.  Other  substances  are  se- 
lected often  when  clay  is  just  as  available.  AVe  saw  a 
severe  case  in  a  girl  whose  father  had  tried  in  vain  in  every 
wa}^  possible  to  break  her  from  eating  coffee  grounds 
thrown  out  the  window.  She  would  often  steal  the 
"grounds"  from  the  pot  if  it  was  not  put  out  of  her 
reach  after  the  coffee  was  drained  off,  though  she  did  not 
drink  coffee.  The  habit  was  cured  in  a  short  time  by 
thymol  administration,  which  resulted  in  the  expulsion  of 
several  hundred  hookworms.  While  many  patients  with 
hookworm  disease  have  the  capricious  appetite  and  the 
habit  of  geophagy,  there  are  many  even  severe  cases  that 
never  take  up  such  habits.  It  is  seldom  that  a  child  or 
adult  guilty  of  the  habit  will  acknowledge  it,  due,  no  doubt, 
to  fear  of  chastisement  or  to  shame. 

A  good  deal  of  work  has  been  done  on  the  gastric  secre- 
tions by  Japanese  investigators.  Yoshida  (1908)  gives  re- 
sults in  101  Formosans  and  Chinese,  comparing  them  with 
those  in  people  on  similar  diet,  and  finds  that  in  ankylos- 


SYMPTOMATOLOGY.  149 

toniiasis  the  total  acidity  is  most  often  normal,  hyperacidity 
rare,  and  subaciditv  still  rarer.  Free  HCl  is  usually  nor- 
mal, and  subacidity  more  frequent  than  hyperacidity.  No 
exact  relations  between  anemia  and  HCl  could  be  made  out, 
but,  with  some  exceptions,  the  more  intense  the  anemia  the 
lower  the  free  HCl.  In  the  cases  examined  there  was  a  re- 
lation between  appetite  and  free  HCl  in  the  stomach  con- 
tents. 

Diarrhea  occurs  in  the  first  few  weeks  of  an  acute  infec- 
tion in  many  instances,  but  is  not  a  symptom  of  chronic 
hookworm  disease,  excei^t  in  ver}'  severe  cases,  in  which  it 
is  not  uncommon.  Constipation  is  often  present,  but  we 
doubt  if  it  is  more  than  an  accidental  symptom.  Children 
under  the  age  of  puberty  are  often  "pot  bellied"  when  they 
have  the  chronic  severe  type.  This  is  due  to  dilatation  of 
the  stomach  and  intestines  chiefly,  and  partly  to  excessive 
mesenteric  fat.  Only  children  with  chronic  infections  have 
this  symptom. 

McG-ehee  has  reported  a  case  in  which  hookworms,  but 
no  ova,  were  found  in  an  appendix  vermiformis,  the  seat  of 
a  catarrhal  inflammation. 

The  feces  contain  the  ova,  which  have  been  more  fully 
described  in  the  chapter  on  Diagnosis.  They  also  contain 
minute  traces  of  blood,  which,  however,  can  not  be  made  out 
macroscopically  or  microscopically,  except  in  the  severest 
cases.  Even  the  mild  cases  will  usually  give  a  positive  reac- 
tion for  occult  blood  in  the  feces,  provided  a  very  delicate 
test  for  blood  is  made,  such  as  Adler's  benzidin  test.  A  con- 
venient way  of  performing  this  test  is  to  add  to  a  few  (5  to 
10)  cubic  centimeters  of  liquefied  feces  1  or  2  cubic  centi- 
meters of  glacial  acute  acid  and  5  to  10  cubic  centimeters 
of  sulphuric  ether.  Mix  without  shaking,  then  pour  off  the 
supernatant  ether  and  test  it  by  adding  a  few  drops  of 
strong  hot  alcoholic  solution  of  benzidin  and  1  or  2  cubic 


150  HOOKWORM  DISEASE. 

centimeters  of  peroxide  of  hydrogen.  In  tlie  presence  of 
blood,  even  in  minute  quantities,  a  blue  color  will  promptly 
follow. 

Genito-urinary  system. — The  genitourinary  organs  are 
delayed  m  their  development  in  proportion  to  the  general 
developmental  impairment.  Boys  develop  later,  accord- 
ingly to  the  severity  of  the  disease,  and  girls  begin  to  men; 
struate  later  than  normal — often  in  severe  cases  this  func- 
tion is  not  established  until  they  are  16  to  18  years  old. 
Amenorrhea  and  scanty  and  irregular  menstruation  are 
common.  There  are  instances  in  which  pregnancy  occurred 
before  menstruation  was  established.  In  girls  the  breasts 
share  the  general  retardation  m  development. 

The  quantity  of  urine  is  uninfluenced  until  the  very  severe 
degree  of  the  disease  is  reached,  when  the  reduction  is 
often  great  and  general  anasarca  supervenes.  Albumin  is 
often  present  in  small  amounts  in  patients  with  hemoglobin 
below  50  or  60  percent,  and  often  in  the  very  severe  cases 
is  present  in  very  large  amounts.  We  have  seen  several 
times  from  40  to  50  and  60  percent  of  moist  albumin  hj  the 
Purdy  ferrocyanide  test.  Casts  are  strikingly  absent,  but 
sometimes  may  be  seen  in  the  very  severe  cases.  We  have 
seen  a  case  with  60  percent  of  albumin  and  extreme  dropsy 
in  which  no  casts  were  found  on  repeated  examinations. 
General  dropsy  is  common  in  very  severe  and  almost  all 
fatal  cases,  and  often  is  extreme.  There  is  more  or  less 
puffiness  of  the  loose  tissue  of  the  face,  feet,  and  legs  in  most 
cases  with  hemoglobin  below  50  percent.  When  hookworm 
patients  get  pregnant,  the  tendency  to  dropsy  is  very  much 
increased  by  the  disease,  and  in  severe  cases  the  swelling  is 
often  great.  Swelling  of  the  labia  is  especially  troublesome 
as  the  pregnancy  approaches  term. 

Lactation  is  impaired  according  to  the  degree  of  anemia. 
Mothers  are  often  unable  to  properly  nourish  their  children. 


SYMPTOMATOLOGY.  151 

The  promptness  with  which  this  function  improves  after 
treatment  is  striking — often  actually  faster  than  improve- 
ment of  the  anemia. 

Eyes. — The  eye  grounds  showed  changes  in  7  to  8  percent 
of  cases  examined  by  Lutz.  Menche  found  that  the  tem- 
poral half  of  the  visual  field  showed  obscurity.  Neurore- 
tinitis  has  been  reported.  Nieden,  of  Bochum,  Westphalia, 
has  shown  that  patients  with  hookworm  often  have  retinal 
hemorrhages,  such  as  occur  in  pernicious  anemia.  They 
occur  especially  and  early  in  the  peripheral  parts  rather 
than  near  the  papilla  and  the  macula,  are  punctate,  often 
in  groups,  without  any  tendency  to  confluence.  Sometimes 
they  accompany  the  vessels  close  up  to  the  papilla.  In  long 
standing  and  severe  cases  there  are  larger  plaques  of  ex- 
travasation, with  radiating  edges.  Along  with  the  hemor- 
rhages are  the  usual  changes  of  anemia,  such  as  pallor  of 
the  retina,  porcelain-like  papilla,  tortuous  vessels,  often 
strongly  pulsating.  The  disturbances  of  vision  are  due 
rather  to  the  general  alterations  than  to  those  in  the  retina. 
Asthenopia,  paresis  of  the  internal  or  external  recti,  dip- 
lopia, vertigo,  nystagmus,  and  hemeralopia  (or  night  blind- 
ness) may  occur.  Concentric  contraction  of  the  visual 
fields  has  been  noted.  Nieden  and  others  look  on  the  retinal 
hemorrhages  as  evidence  of  toxic  processes.  Stiles  has 
called  attention  to  the  appearance  of  the  pupil.  He  says: 
'^If  the  patient  is  directed  to  stare  intently  into  the 
observer's  eyes,  there  will  be  noticed  a  symptom  which  it 
is  difficult  to  describe,  but  which  I  have  found  more  constant 
than  almost  any  other  noticed — namely,  after  a  moment, 
the  length  of  time  apparently  varying  slightly  according 
to  the  degree  of  the  disease,  the  pupils  dilate  and  the 
patient's  eyes  assume  a  dull,  blank,  almost  fish-like  or 
cadaveric  stare,  very  similar  to  that  noticed  in  cases  of 
extreme  alcoholic  intoxication."     Ashford  and  King  found 


152  HOOKWORM  DISEASE. 

dilatability  of  the  pupil  noticeable  in  their  Porto  Rico  cases. 
AVe  have  often  noticed  that  the  pupil  dilates  readily,  and 
usually  remains  wide,  even  in  the  presence  of  considerable 
light,  but  this  is  a  common  symptom  of  all  severe  anemias. 

Nervous  system. — Nervous  and  mental  symptoms  of 
various  kinds  are  not  infrequently  present  in  hookworm 
patients,  and  sometimes  cause  great  diagnostic  difficulty. 
There  are  few,  if  any,  nervous  symptoms,  however,  that  can 
not  be  ascribed  to  the  anemia.  There  is  a  general  benumb- 
ing of  the  mental  faculties  in  acute  cases,  but  the  chronic 
hookworm  child  is  generally  well  up  in  mentality  with 
others  of  his  size  and  vigor,  but  usually  not  equal  to  those 
of  his  age.  In  the  acute  and  very  severe  form  the  disease 
produces  often  melancholia,  hypochondriasis,  and  a  careless 
expression.  Insomnia  and  night  terrors  are  very  common, 
due,  no  doubt,  to  feeding  and  moving  about  by  the  worms, 
which  the  nervous  system  feels  more  when  the  patient  is 
perfectly  quiet,  as  in  sleep,  than  when  active.  Somnolence, 
on  the  other  hand,  often  occurs,  and  the  patient  keeps  awake 
in  day  time  with  difficulty.  Lack  of  ambition  is  noticeable, 
and  has  given  rise  to  the  idea  that  the  patient  is  laz}^ 
Hookworm  patients  do  not  work  as  much  or  as  well  as  those 
not  infected,  but  it  is  because  they  are  sick  and  not  because 
they  are  lazy.  In  the  last  few  years  a  great  deal  has  been 
said  in  the  newspapers  jokingly  about  the  "lazy  disease," 
and,  if  the  same  amount  of  publication  had  been  devoted  to 
dissemination  of  knowledge  of  the  sources  and  the  preven- 
tion of  the  disease,  there  is  no  doubt  that  it  would  be  less 
prevalent  today. 

Signorelli  (1909)  reports  some  interesting  cases.  In  one, 
a  boy  of  10,  with  mild  anemia,  had  a  meningeal  syndrome, 
with  headache,  vomiting,  neuromuscular  hyperesthesia, 
cervical  rigidity,  Kernig's  sign,  etc.,  cured  by  thymol.  A 
girl  of  17,  with  neuralgia,  especially  crural,  anesthesia,  and 


SYMPTOMATOLOGY.  153 

paresthesia,  was  quickly  cured  by  thymol  after  the  blood 
count  showed  30  percent  of  eosinophiles  and  the  anamnesis 
revealed  previous  residence  in  Brazil.  In  another  case,  a 
woman  of  23,  vasomotor  disturbances  and  epileptiform  con- 
vulsions were  equally  amenable  to  specific  treatment  with 
thymol.  Signorelli  emphasizes  the  tendency  of  hookworm, 
like  the  malarial  parasite,  to  cause  vasomotor  abnormalities. 

Austregesilo  and  Gotuzzo  (Eio  de  Janeiro,  1909)  call  at- 
tention to  the  possibility  of  severe  psychic  alterations  in 
ankylostomiasis.  They  report  the  case  of  a  man  of  26,  free 
from  history  of  alcohol  or  syphilis,  who  became  apathetic 
and  melancholic,  later  complained  of  severe  and  continued 
pain  in  head  and  abdomen,  and  of  dyspnea  and  fatigue  on 
exertion,  and  finally  had  delusions  of  poisoning.  Severe 
anemia  with  eosinophilia  led  to  thymol  treatment  and  to 
complete  recovery.  In  another  case  there  were  many  evi- 
dences of  psychic  degeneration,  with  loss  of  memory,  re- 
ligious hallucinations,  and  delirium  of  grandeur.  Anemia 
and  18  percent  of  eosinophiles  suggested  thymol  treatment, 
and  complete  recovery  followed.  In  another,  with  hemo- 
globin 35  percent,  red  blood  corpuscles  3,100,000,  and  eosino- 
philes 16,  there  was  complete  loss  of  sense  of  time  and  place. 
Later,  the  condition  described  by  Oppenheim  as  ''Witzel- 
sucht"  developed.  The  patient  was  ironic  and  sarcastic, 
ridiculed  everything  and  everybody.  Improvement  of  the 
ankylostomiasis  coincided  with  that  of  the  mental  condition, 
and  finally  both  were  cured. 

MacDonald,  in  Australia  (1908),  has  seen  various  perver- 
sions besides  dirt  eating  among  hookworm  patients,  espe- 
cially children,  mentioning  disobedience,  profanity,  lying, 
stealing,  drinking,  forging,  and  sexual  perversions.  These, 
of  course,  are  not  rare  manifestations  without  hookworm, 
but  the  important  thing  is  that  in  the  cases  reported  re- 
covery followed   cure  of  the  hookworms.     The  youngest 


154  HOOKWORM  DISEASE. 

patient  was  only  8  months  old.  Allan  has  called  attention 
to  the  frequent  association  of  neurasthenia  and  hookworm, 
as  might  be  expected.  It  would  be  interesting  to  make 
observations  on  the  psychic  reactions  of  such  cases  of 
various  dfegrees  of  severity.  Perhaps  some  of  the  exuber- 
ant lawlessness  of  hookworm  regions  may  be  due  to  the  lack 
of  control  caused  by  the  infection. 

Sodre,  and  also  Austregesilo  and  Gotuzzo,  suggest  that 
the  parorexia  of  hookworm  infection  is  an  evidence  of  the 
altered  mental  condition,  rather  than  the  direct  result  of  the 
disease  in  the  intestinal  tract. 

Finally,  we  want  to  emphasize  the  fact  that  hookworm 
disease  is  likely  to  have  associated  with  it  other  diseases, 
and  the  symptoms  of  each  be  altered  by  the  other.  All 
symptoms  presented  by  a  hookworm  patient  must  not  neces- 
sarily be  attributed  to  this  disease.  On  the  other  hand,  a 
part  of  the  symptoms  in  cases  having  other  diseases  may  be 
due  to  hookworm  disease. 


CHAPTER  VII. 

DIAGNOSIS. 

"The  secret  of  the  diagnosis  of  ankylostomiasis,  like  that 
of  many  other  diseases,  is  to  suspect  its  presence." 
(Manson.) 

An  absolutely  certain  diagnosis  of  hookworm  infection 
can  not  be  made  without  finding  the  eggs  or  worms  in  the 
feces.  It  is  possible,  however,  to  diagnose  it  symptomatic- 
ally  with  reasonable  certainty  in  most  cases  showing  well- 
marked  symptoms,  provided  this  disease  is  kept  in  mind. 
The  combination  of  the  characteristic  anemia  associated 
with  underdevelopment,  weakness,  dilated  heart,  and  a 
history  of  ground  itch  is  not  likely  to  be  confounded  with 
anything  else.  We  can  not  emphasize  too  forcibly  the  im- 
portance of  this  history  of  ground  itch,  or  ''toe  itch,"  with- 
in the  preceding  years.  In  all  patients  from  warm  climates 
presenting  anemia  and  impaired  development  without 
obvious  cause  this  should  be  inquired  for.  Whenever  a 
history  of  toe  itch  is  obtained,  nothing  short  of  thorough 
examination  of  the  feces  for  eggs  permits  elimination  of 
hookworm  from  the  diagnosis. 

A  history  of  ground  itch,  or  hookworm  disease,  aifecting 
other  members  of  an  individual's  family,  or  those  living  on 
the  same  plantation  or  in  the  same  surroundings,  usually 
indicates  that  the  patient  is  also  infected,  though  he  never 
had  ground  itch  himself. 

The  history  of  going  barefoot  during  the  summer  in  a 
locality  known  to  be  infected  usually  means  that  the  pa- 
tient is  infected,  though  he  has  not  had  a  definite  attack  of 

155 


156  HOOKWOEM  DISEASE. 

ground  itcli.  So  few  larvae  may  enter  the  skin  at  a  time  as 
not  to  produce  recognizable  or  characteristic  lesions. 

In  infected  localities,  as  Tenholt  found  among  miners 
in  infected  mines,  and  Stiles  in  his  journeys  through  the 
southern  "United  States,  the  diagnosis  of  hookworm  disease 
can  often  be  made  by  inspection,  and  will  turn  out  to  be  cor- 
rect in  the  majority  of  cases.  In  such  places,  where  time 
for  examination  is  short,  treatment  may  be  carried  out  on 
the  ground  of  the  symptomatic  diagnosis  and  the  accurate 
diagnosis  made  by  examining  the  stools  for  worms  after- 
ward. The  diagnosis  of  cases  can  be  made  almost  as  ac- 
curately from  the  great  imiDrovement  after  thymol  treat- 
ment. This  sort  of  diagnosis,  however,  can  not  be  looked 
on  as  satisfactory  or  scientific,  nor  will  it  discover  the  im- 
portant class  of  hookworm  carriers. 

Though  the  diagnosis  may  be  indicated  by  the  history  and 
symptoms  present  in  all  well-marked  cases  of  hookworm 
disease,  these  fail  in  a  large  number  of  cases  that  have  not 
obvious  symptoms,  either  because  of  small  number  of 
worms,  or  because  of  more  or  less  immunity  to  the  effects 
of  the  worms.  The  most  practical  and  satisfactory  way 
of  arriving  at  a  certain  diagnosis  is  by  examining  the  feces 
for  ova  of  the  parasite.  These  are  characteristic,  easily 
recognized,  and,  when  worms  are  present  in  sufficient  num- 
bers and  under  such  conditions  as  to  cause  symptoms,  are  so 
easily  found  that  the  diagnosis  becomes  one  of  the  most 
simple  procedures  in  the  practice  of  medicine,  provided  one 
is  equipped  with  a  microscope  and  proper  knowledge  and 
experience,  which  can  be  easily  acquired.  The  microscopic 
examination  of  feces  is  of  so  much  importance  in  diagnosis 
that  we  believe  a  complete  description  of  every  detail  is 
warranted,  including  descriptions  of  the  many  things  likely 
to  be  mistaken  for  or  confused  with  hookworm  eggs. 


DIAGNOSIS,  157 

Obtaining-  Specimens  for  Examination. 

The  quantity  of  feces  needed  for  a  microscoiDic  examina- 
tion, even  when  the  most  comprehensive  examination  de- 
scribed on  ]jages  171  to  177  is  to  be  made,  need  not  exceed 
two  or  three  drams  at  most.  Unless  instructed  on  this  point, 
the  patient  will  often  bring  or  send  large  quantities  or  the 
whole  stool  in  fruit  jars,  large  pickle  jars,  etc.  Large  ves- 
sels of  feces  are  much  more  exposed  to  accidents — such  as 
breaking  or  spilling,  especially  when  the  feces  are  liquid — 
than  smaller  ones.  More  malodorous  gases  are  given  off 
from  a  large  amount  of  feces  than  from,  say,  one-twentieth 
of  this  quantity.  The  opening  ujd  and  handling  of  a  small 
quantity  of  feces  in  the  laboratory  or  office  is  not  nearly  so 
unpleasant  as  handling  a  much  larger  quantity.  It  is  not 
sufficient  to  tell  the  patient  to  bring  only  a  small  quantity. 
This  point  must  be  impressed  on  him  when  requesting  him 
to  bring  the  specimen.  He  should  be  told  to  bring  only  a 
small  quantity  of  the  actual  feces,  and  the  physician  should 
make  this  more  certain  by  furnishing  him  with  a  suitable 
receptacle  in  which  to  bring  or  send  the  specimen,  and  when 
it  is  given  him  to  explain  that  he  wants  only  a  small  quan- 
tity in  it  and  not  to  fill  it  full.  Vaseline  bottles,  two-dram 
quinine  bottles,  or  other  low  form  wide-mouth  bottles  serve 
the  purpose  well.  One  who  expects  to  have  many  specimens 
of  feces  brought  to  him  by  his  patients  should  provide  him- 
self with  a  proper  supply  of  two-ounce  wide-mouth  bottles 
with  corks.  They  are  also  appropriate  for  sj^utum  bottles. 
These  should  never  be  used  a  second  time.  Wide-mouth 
bottles  also  have  a  great  advantage  in  permitting  feces  to 
be  put  in  and  taken  out  of  them.  Moreover,  when  feces  are 
put  in  a  narrow-mouth  bottle,  they  usually  lodge  partly  in 
the  neck,  and,  after  the  stopper  is  put  in,  gases  form  which 
often  blow  out  the  cork  and  feces,  soiling  anything  or  any- 


158  HOOKWORM  DISEASE. 

body  near  by.  When  bottles  are  entirely  filled  with  feces, 
especially  if  liquid,  the  stopper  is  very  likely  to  be  blown 
out  when  the  package  is  unwrapped,  if  not  before.  If  only 
partly  filled,  this  is  not  so  likely  to  occur. 

,       Kind  of  Feces  to  be  Examined. 

Any  kind  of  a  stool  will  do  for  examination,  but  there  are 
reasons  for  preferring  the  formed  feces  instead  of  liquid 
material.  These  reasons  are  that  the  preparation  on  the 
microscope  slide  can  be  more  satisfactorily  made  with 
formed  feces;  that  liquid  feces  are  more  odorous  and 
more  likely  to  get  out  of  the  bottle  accidentally;  and 
that  eggs  sometimes  tend  to  settle  to  the  bottom  of 
a  liquid,  and  greater  care  is  therefore  necessary  in  mak- 
ing the  preparation  on  the  slide;  and  that,  if  the  speci- 
men is  very  liquid,  eggs  are  likely  to  precipitate  and  stick 
to  the  bottom  and  sides  of  the  bottle,  and  be  missed  when 
only  a  few  eggs  are  present,  in  spite  of  considerable  agita- 
tion. Pepper  has  called  attention  to  the  peculiarity  pos- 
sessed by  hookworm  eggs  of  sticking  to  the  slide  after  they 
have  once  settled  in  a  slide  preparation.  One  who  wishes  to 
thoroughly  familiarize  himself  with  examination  of  stools 
for  hookworm  eggs  should  try  this  for  himself.  Place  on  a 
slide  some  sediment  from  centrifuging,  described  on  page 
173,  containing  hookworm  eggs.  Dip  or  invert  the  slide 
in  a  beaker  of  water  after  allowing  the  material  to  settle 
a  few  minutes.  Now  examine  the  slide  under  the  micro- 
scope, and  the  eggs  will  be  found  to  have  stuck  to  tile  slide 
even  after  considerable  agitation,  though  everything  else 
came  off. 

Making-  the  Preparation  for  Microscopic  Examination. 

For  the  examination  of  feces  the  ordinary  3-inch  slides 
are  too  small  for  the  most  satisfactory  manipulation.     We 


DIAGNOSIS.  159 

prefer  2x3-mc]i  slides,  or  even  larger.  Photographic  nega- 
tive glasses  31/4x31/4,  3^/4x41^,  or  4x5  are  all  very  convenient, 
and  usually  easy  to  get.  The  ordinary  1x3  slides,  however, 
serve  the  purpose  well,  especially  if  a  mechanical  stage  is 
used. 

Put  in  the  center  of  a  slide  one  to  three  drops  of  water. 


Fig-.   45.     Diluted  feces  on  slide,  ready  for  microscopic  examination. 

and  with  a  toothpick  take  up  a  quantity  of  feces  about  the 
size  of  a  match  head.  Stir  this  into  the  water  until  it  is 
about  as  cloudy  as  can  be  examined  well  with  the  micro- 
scope, spreading  out  the  diluted  feces  properly  over  the 
slide  at  the  same  time.  The  diluted  feces  should  not  come 
quite  to  the  edge  or  ends  of  the  slide  at  any  point,  as  they 


160  HOOKWOEM  DISEASE. 

would  then  easily  run  off  on  the  hands,  microscope,  etc. 
The  preparation  should  cover  at  least  one-half  the  area  of 
the  slide  if  the  ordinary  1x3  slide  is  used.  (Fig.  45.)  The 
thickness  of  the  mixture  must  be  learned  by  experience,  but 
it  is  desirable  to  have  it  dilute  enough  to  allow  a  good  light 
to  be  had  and  a  clear  outline  of  the  material  on  the  slide.  A 
preparation  that  allows  ordinary  print  to  be  read  through 
with  the  unaided  eye  is  usually  not  too  thick.  It  is  not 
necessary  to  continue  stirring  the  feces  off  the  pick  after  the 
mixture  becomes  of  the  proper  consistency.  If  properly 
manipulated  so  as  to  rub  off  the  feces  gradually,  it  is  easy 
to  stop  at  any  point  desired  and  to  throw  away  any  excess  of 
feces  with  the  j)ick.  Ordinary  toothpicks  are  the  best 
things  we  have  ever  seen  for  making  such  preparations. 
They  have  been  used  for  a  long  time  for  this  and  similar 
purposes  by  many  laboratory  workers.  They  should  be  of 
good  quality  and  have  one  thin  flat  end.  The  same  pick 
should  never  be  used  for  examining  another  specimen  on  ac- 
count of  the  possibility  of  carrying  eggs  from  one  to  the 
other.  Matches  or  other  such  pieces  of  wood  serve  tlie  pur- 
pose also,  but  not  so  well.  A  convenient  way  to  dispose  of 
the  soiled  picks  is  to  burn  the  used  end  over  a  flame,  or  they 
may  be  dropped  into  the  bottle,  which  is  then  stoppered  so 
as  to  avoid  contamination  and  infection. 

Use  of  Cover  Glasses  Unnecessary. 

It  is  unnecessary  to  use  cover  glasses  in  examining  feces 
for  hookworm  or  most  other  parasite  eggs.  With  the  mag- 
nification generally  used  they  are  absolutely  unnecessary. 
It  is  usually  necessary  to  examine  preparations  larger  than 
the  regular  cover  glasses  and  sometimes  several  of  them. 
If  it  is  desired  to  study  a  specimen  with  high  powers  for 
some  special  purpose,  it  is  easy  to  place  a  cover  glass  over 
the  part  to  be  examined,  and  press  it  down  gently  to  thin  it 


DIAGNOSIS.  161 

out.  Cover  glasses  are  also  necessary  if  a  great  deal  of 
time  is  to  be  spent  in  examining  a  given  slide,  to  prevent  the 
preparation  drying  out  so  rapidly. 

Examine  Only  Wet  Preparations. 

The  preparation  is  to  be  examined  wet.  As  soon  as  it 
dries  it  is  useless,  and,  if  this  happens  before  an  examina- 
tion is  completed,  more  water  is  to  be  added,  or  another 
preparation  should  be  made.  A  properly  made  preparation 
can  be  entirely  gone  over  with  the  low  power  lens  before  it 
dries  out  appreciably.  If  spread  out  too  thin,  it  will  dry 
much  more  rapidly.  Most  of  the  solid  particles,  including 
eggs,  if  present,  settle  on  the  surface  of  the  slide  soon 
after  it  is  prepared,  and  are  then  found  about  in  the  same 
level  or  focus,  so  that  the  thicker  the  layer,  provided  it  does 
not  prevent  seeing  through  it,  the  more  concentrated  will  be 
the  objects  on  the  surface. 

Magnification. 

The  low  power  of  any  of  the  commonly  used  microscopes 
is  to  be  employed.  The  2/3  objective  and  1-inch  eyepiece, 
or  the  16-millimeter  objective  and  corresponding  eyepiece, 
give  the  proper  magnification  of  about  100  diameters. 
Higher  magnification  is  undesirable  for  general  work  be- 
cause the  field  is  correspondingly  reduced,  and  therefore  it 
takes  much  longer  to  look  over  a  preparation. 

Time  Required  and  Number  of  Slides  to  be  Examined. 

The  time  required  to  examine  for  eggs  varies  with  the  ex- 
perience and  speed  of  the  examiner,  the  number  of  eggs 
present,  the  thickness  and  size  of  the  preparation,  and 
whether  there  are  many  particles  resembling  eggs,  requir- 
ing close  observation  to  differentiate  them.     If  many  eggs 


162  HOOKWOEM  DISEASE. 

are  present,  the  diagnosis  may  often  be  made  on  the  first 
field  examined,  but  to  stop  after  finding  a  few  hookworm 
eggs  is  not  good  practice.  The  examination  should  be  con- 
tinued to  find,  if  present,  eggs  of  other  parasites  which  are 
likely  to  ^e  present  in  small  numbers,  and  to  get  some  idea 
of  the  number.  When  less  than  ten  female  worms  are  pres- 
ent, there  may  be  an  average  of  less  than  one  egg  to  a  slide. 
It  is  estimated  that  one  actively  laying  female  produces 
two  thousand  to  three  thousand  eggs  in  twenty -four  hours, 
but  many  of  the  worms  lay  much  fewer  eggs  and  a  few  old 
ones  lay  none. 

We  recently  had  each  man  of  several  groups  of  five  medi- 
cal students  examine  five  or  more  slides  of  one  hundred  dif- 
ferent specimens  of  feces,  twenty-nine  of  which  finally 
showed  mild  hookworm  infection.  The  remainder,  seventy- 
one,  were  negative.  Several  instances  occurred  in  which 
only  one  or  two  men  of  the  group  found  one  or  two  eggs  in 
a  particular  specimen.  These  men  had  been  thoroughly  in- 
structed and  practiced  in  the  recognition  of  hookworm  eggs, 
and  it  is  believed  were  not  likely  to  overlook  them.  Eggs 
were  found  in  only  twenty-three  specimens  from  this  exami- 
nation of  twenty-five  slides  of  each.  The  negative  speci- 
mens were  now  examined  after  being  carefully  washed  and 
centrif uged,  and  six  found  to  contain  eggs.  In  this  instance 
examination  of  twenty-five  slides  failed  to  demonstrate  eggs 
in  20  percent  of  the  cases  in  which  they  were  present. 
These  were  the  ordinary  1x3  microscope  slides,  and  the 
specimens  were  from  adults  who  had  very  few  worms — not 
enough  to  produce  any  recognizable  symptoms,  except  in 
one  or  two  instances.  Most  of  them  had  not  been  rein- 
fected in  many  years,  and  their  worms  certainly  were  not 
laying  as  prolifically  as  younger  worms  do. 

Another  group  of  ten  men  were  first  well  drilled  on  the 
diagnosis  of  worm  eggs  and  then  set  to  work  to  examine 


DIAGNOSIS.  163 

oue  hundred  and  thirty-six  specimens  of  feces  that  showed 
on  final  examination  fifty-eight  infected,  as  follows:  six 
hookworm,  thirty-two  trichocephalus,  eight  tenia  nana, 
twelve  oxyuris.  One  to  five  slides  were  examined — an 
average  of  two  or  three.  Thirty-one,  or  53  percent,  of  the 
specimens  containing  eggs  were  diagnosed  negative  by  this 
examination.  They  were  mild  infections,  and  all  these 
worms  other  than  hookworms  lay  comparatively  few  eggs, 
as  is  well  known.  These  figures  show  that  examining  two 
or  three,  or  even  twenty-five,  ordinary  slide  preparations 
is  not  sufficient  to  discover  eggs  every  time  when  very  few 
are  present.  It  is  necessary  to  examine  at  least  six  to  ten 
slides  before  a  practical  negative  diagnosis  can  be  made, 
but,  if  one  hundred  or  more  worms  are  present,  eggs  can  be 
found  in  every  slide,  except  under  rare  conditions.  The 
number  of  worms  in  many  well-marked  or  severe  cases  is 
from  one  thousand  to  four  thousand,  and  eggs,  often  several, 
can  be  found  in  almost  every  microscope  field.  We  can  look 
over  thoroughly  an  ordinary  slide  in  two  to  four  minutes. 
We  have  seen  comparative  beginners  become  able,  with  a 
few  days  of  practice,  to  examine  well  one  slide  in  six  to  ten 
minutes. 

Light. 

The  amount  of  light  used  should  be  that  giving  the  best 
detail  to  the  small  particles  in  the  preparation.  On  an 
ordinarily  bright  day,  or  with  artificial  light,  the  maximum 
light  available  when  using  any  standard  microscope  will  be 
entirely  too  strong,  and  must  be  reduced  by  partly  closing 
the  iris  diaphragm  under  the  Abbe  condenser.  The  light 
is  increased  or  decreased  with  this  diaphragm  after  the  re- 
flector has  been  adjusted  so  as  to  reflect  directly  all  the  light 
falling  upon  it.  The  light  should  be  such  as  permits  eggs, 
when  present,  to  be  seen  well  in  detail.     The  outline  of  the 


164  HOOKWOEM  DISEASE. 

yolk  and  shell  should  be  distinct,  and  the  clear  albumen 
space  should  be  well  shown.  With  too  bright  a  light  the 
whole  egg  is  blurred  and  indistinct. 

Method  of  Going  Over  the  Slide. 
■J 

If  a  mechanical  stage  is  used,  it  is  a  good  plan  to  begin 
at  one  side  of  a  preparation  and  to  move  the  slide  systemat- 
ically from  end  to  end,  moving  back  or  forth  the  width  of  a 
field  every  time  the  end  is  reached  until  the  entire  slide  has 
been  gone  over.  With  a  large  slide,  or  if  no  mechanical 
stage  is  used,  the  slide  should  be  moved  in  the  same  manner 
with  the  fingers.  With  practice  and  with  low  power,  this 
can  be  readily  done. 

Description  of  Eggs. 

The  ova  of  uncinaria  Americana  are  ellipsoid,  fifty-four 
to  seventy-two  microns  long  by  thirty-six  to  forty  microns 
broad,  in  some  cases  partially  segmented  in  utero.  The 
ova  of  ankylostoma  duodenale  are  ellipsoid,  fifty-six  to 
sixty-one  microns  by  thirty-four  to  thirty-eight  microns, 
laid  in  segmentation.  The  two  varieties  have  practically 
the  same  general  appearance,  and  can  not  be  differentiated 
except  by  careful  measurement.  Uncinaria  Americana 
eggs  are  said  to  be  more  pointed  at  the  poles.  (Looss.) 
Eggs  may  be  seen  lying  flat,  or  they  may  be  on  end,  in 
which  case  they  appear  round.  There  are  all  variations 
between  these  extremes,  in  which  they  appear  shorter  than 
normal,  due  to  their  being  seen  in  an  oblique  position  on 
the  slide.  With  experience  a  mental  picture  of  the  size  is 
formed,  which  is  all  the  guide  to  size  necessary.  Different 
individuals  see  the  size  of  things  under  the  microscope  dif- 
ferently. To  our  eye,  with  a  1-inch  eyepiece  and  a  2/3-inch 
objective,  hookworm  eggs  seem  to  be  three-eighths  to  one- 
half  inch  long  by  about  one-fourth  less  than  this  in  diam- 


DIAGNOSIS.  165 

eter.  The  outline  of  the  chitinoiis  shell  is  smooth  and  regu- 
lar, and  shows  as  a  narrow  band.  The  regularity  in  out- 
line of  the  shell  often  serves  to  differentiate  them  from  the 
capsular  membrane  enveloping  the  chlorophyl  of  many  dif- 
ferent varieties  of  vegetable  cells.  The  yolk  is  made  up  of 
fine  granular  dark  gray  material  and  contains  a  central 
lighter  area.  When  seen  sufficiently  early,  the  yolk  is  of 
the  same  shape  as  the  egg  shell,  and  usually  situated  about 
the  same  distance  from  it  on  all  sides.  There  is  a  distinct 
clear  albumen  space  between  the  shell  and  yolk  from  one- 
eighth  to  one-fifteenth  as  wide  as  the  diameter  of  the  egg. 
Most  of  the  eggs  begin  to  segment  before  the  feces  are  dis- 
charged, and  therefore  those  found  in  fresh  material  con- 
tain two,  four,  or  eight,  or  more  segments.  (Figs.  11,  13.) 
In  older  stools  embryos  may  be  seen  inside  of  the  egg  shell, 
nearly  ready  to  come  out  and  moving  around  slowly  in  their 
shell,  which  they  nearly  fill.  (Fig.  11.)  For  a  complete 
description  of  the  embryos  and  larvas  see  the  chapter  on 
zoology. 

Number  of  Worms  Indicated  by  Number  of  Eggs. 

Leichtenstern  has  proposed  to  estimate  the  number  of 
worms  present  by  the  number  of  eggs  found  in  the  feces. 
He  divides  the  number  of  ova  contained  in  one  gram  of 
feces  by  the  factor  forty-seven.  Grassi  and  Parona  esti- 
mate the  number  of  eggs  in  one  centigram  of  feces  and  cal- 
culate the  number  of  worms,  assuming  that  one  hundred 
and  fifty  to  one  hundred  and  eighty  eggs  per  centigram  rep- 
resent one  thousand  worms. 

Ashford  and  King  have  called  attention  to  the  fact  that 
certain  things  may  prevent  the  correct  estimation  of  worms 
by  the  eggs  present.  They  well  say  that  the  worms  cause 
an  increase  of  mucus  at  the  site  of  their  feeding  ground, 
and,  as  this  mucus  often  comes  off   en  masse  and  contains 


166  HOOKWORM  DISEASE. 

most  of  the  eggs,  the  actual  feces  would  contain  relatively 
few.  They  sa^^  eggs  are  more  difficult  to  find  in  diarrheal 
stools  for  some  reason  or  other,  and  in  this  connection  we 
mention  the  fact  that  the  quantity  of  feces  passed  by  differ- 
ent individuals  varies  greatly  with  the  size  and  age,  the 
kind  and  amount  of  food  eaten,  the  digestive  ability  of  the 
patient,  and  also  with  the  water  intake  and  elimination,  in- 
testinal bacterial  flora,  etc.  Ashford  and  King  saw  cases  of 
heavy  infection  that  at  times  had  no  ova  in  their  feces, 
especially  soon  after  thymol  had  been  given,  but  they  also 
had  patients  with  many  ova  two  days  after  full  thymol 
treatment.  With  us  it  has  been  a  common  experience  to 
have  a  patient's  feces  reported  negative  within  a  few  days 
after  a  course  of  thymol  and  on  subsequent  examination 
eggs  be  found  in  large  numbers.  This  is  more  likely  to 
occur,  of  course,  when  the  examination  is  not  thorough.  In 
one  instance  after  a  course  of  thymol  the  most  exhaustive 
examination  revealed  no  eggs  one  and  two  weeks  afterward. 
The  patient  remained  in  the  city,  and  therefore  was  not  ex- 
posed to  reinfection.  It  was  winter,  during  which  infec- 
tion does  not  usually  occur.  Six  weeks  after  the  thymol 
ova  were  again  found,  and  one  hundred  and  nineteen  male 
and  female  worms  were  expelled  as  the  result  of  another 
course  of  thymol.  Dieminger  found  that  the  number  of 
eggs  was  very  much  diminished  when  patients  were  drink- 
ing hard.  He  examined  twenty-one  men  on  Monday  and 
found  only  four  infected;  on  the  following  Friday  he  found 
many  ova  in  eleven  who  had  shown  none  on  Monday.  In 
another  instance  he  found  a  man  heavily  infected  on  Sat- 
urday, but  on  the  following  Monday  he  could  find  no  ova 
after  repeated  search.  The  reason  he  assigns  is  that  these 
men  had  been  drinking  to  excess  on  Sunday.  It  is  not  im- 
probable that  the  activity  of  egg  production  by  hookworms 
is  influenced  by  season  of  the  year.     Salt  herring  or  other 


DIAGNOSIS.  167 

very  salty  food  also  has  some  effect.  One  of  us  (Bass)  has 
recently  reported  the  examination  of  two  hundred  and 
forty-seven  female  uncinaria  Americana,  7  percent  of  which 
contained  no  ova,  and  suggested  the  possibility  of  old  age 
being  the  cause.  Dr.  Stiles,  in  discussing  this  question  at 
the  recent  Hookworm  Conference  in  Atlanta,  1910,  said  he 
was  not  prepared  to  say  whether  the  worms  live  long  after 
old  age  induces  cessation  of  ovulation,  but,  reasoning  from 
analogy,  he  did  not  think  this  probable.  Though  animals 
highest  in  the  scale  cease  to  ovulate  at  the  end  of  about  two- 
thirds  of  their  usual  life,  it  is  not  probable  that  any  lower 
forms  do  this,  at  least  to  the  same  extent.  We  have  recently 
examined  three  hundred  and  ninety-seven  female  uncinaria 
Americana  from  patients  whose  ages  and  histories  indicate 
that  they  have  not  been  reinfected  for  several  years,  and 
these  showed  9  1/4  percent  of  barren  worms,  whereas  three 
hundred  and  twenty  dog  uncinaria  from  young  dogs  showed 
only  1/3  percent  without  eggs.  It  is  very  doubtful,  how- 
ever, whether  a  patient  may  be  infected  with  any  consider- 
able number  of  worms  without  a  few  eggs  being  present  in 
the  feces  and  always  demonstrable  by  thorough  examina- 
tion. However,  we  believe  the  possibility  of  only  a  very 
few  old  worms  being  present  is  to  be  thought  of  in  cases 
with  a  history  indicating  previous  existence  of  the  disease 
and  persistence  of  symptoms.  This  may  explain  some  of 
the  cases  of  persistence  of  eosinophilia  and  other  symptoms, 
though  no  eggs  are  present.  If  such  cases  occur,  the  only 
way  to  clear  up  the  diagnosis  positively  would  be  to  give  a 
course  of  treatment  and  examine  the  feces  thoroughly  for 
worms. 

Differentiation  of  Uncinaria  Eggs  from  Other  Ova,  Etc. 

The  eggs  of  uncinaria  are  easily  differentiated  from  those 
of  other  parasites,  except  possibly  strongyloides.     Stron- 


168  HOOKWORM  DISEASE. 

gyloides  eggs  have  the  shape  and  appearance  of  hookworm 
eggs,  and  measure  about  seventy  microns  long  by  thirty-five 
microns  thick.  The  shell  is  clear,  but  yellow.  They  are 
seldom  seen,  because  they  almost  alwa3^s  hatch  while  in  the 
intestine  and  sometimes  before  they  are  expelled  from  the 
uterus,  and  when  an  egg  is  found  there  are  also  to  be  found 
in  the  feces  thousands  of  strongyloides  larvse.  These  can 
not  be  easily  differentiated  from  uncinaria  larvae,  but,  if  it  is 
remembered  that  uncinaria  larvas  are  not  found  in  fresh 
feces,  little  difficulty  is  experienced.  If  the  stool  is  suf- 
ficiently old  (twenty-four  hours  or  longer)  for  uncinaria 
larvae  to  have  hatched  out,  there  will  still  be  present  in  any 
specimen  of  undiluted  feces  far  more  eggs  than  larvae — a 
thing  never  seen  with  strongyloides.  Strongyloides  larvae 
are  differentiated  from  uncinaria  larvae  by  the  presence  of 
a  larger  double  dilatation  of  the  esophagus  and  by  the  de- 
velopment of  the  filariform  stage  when  the  material  is  kept 
for  six  or  eight  hours  or  longer.  The  primordium,  which 
later  develops  into  the  sexual  organs,  is  seen  at  about  the 
middle  of  the  body  of  each,  but  in  strongyloides  it  is  large 
and  oval,  whereas  in  uncinaria  it  is  small  and  round.  They 
develop  long  (four-tenths  to  seven-tenths  of  an  inch),  nar- 
row, very  active  worms,  with  an  esophagus  almost  one-half 
their  length.  Hookworm  larvae,  on  the  other  hand,  become 
encapsuled  in  four  to  five  days.  Double  infection  may 
occur.  Ascaris  lumbricoides  eggs  are  larger,  fifty  to  sev- 
enty microns  long  by  forty  to  fifty  microns  thick,  have  a 
thick,  rough,  albuminous,  bile-stained  coating  of  the  shell, 
are  more  oval,  and  have  less  albumen  space.  Tricho- 
cephalus  eggs  are  smaller,  about  fifty  by  twenty-three 
microns,  more  oblong,  and  have  a  cap  on  each  end,  "lemon 
shaped."  Oxyuris  eggs  are  smaller,  fifty  by  twenty  mi- 
crons, more  oblong,  and  have  a  relatively  smaller  nucleus. 
One  side  is  straight  and  the  other  curved,  and  one  end  is 


DIAGNOSIS.  169 

smaller  than  the  other.  They  are  more  refractile,  giving 
them  a  shining  appearance,  and  slightly  yellow.  Most  of 
the  eggs  seen  are  empty  shells  from  which  the  embryo  has 
already  escaped.  Tenia  eggs  are  smaller,  have  a  thick  shell 
consisting  of  an  inner  and  an  outer  membrane,  between 
which  there  is  a  thick  layer  of  albuminous  material.  In 
tenia  saginata,  tenia  solium,  and  tenia  diplogonoporus 
grandis  this  is  distinctly  striated,  while  the  tenia  nana  has 
only  a  few  longitudinal  bands  running  through  this  part 
of  the  egg,  starting  from  the  poles.  All  have  booklets 
or  the  resemblance  of  booklets  in  their  nuclei.  Bothrio- 
cephalus  latus  eggs  measure  about  forty-five  by  sixty-eight 
to  seventy-one  microns,  and  the  nucleus  entirely  fills  th^ 
shell.  They  are  brown,  and  a  cap  or  lid  can  be  seen  at 
one  end. 

The  beginner  often  has  difficulty  in  differentiating  from 
eggs  various  vegetable  cells  and  sometimes  other  food 
material,  balls  of  bacteria,  etc.  After  fixing  a  correct 
mental  picture  of  the  size  and  shape  of  hookworm  eggs  by 
studying  known  specimens,  including  the  appearance  of  the 
nucleus,  and  observing  the  rule  that  nothing  is  to  be  called 
an  egg  that  does  not  consist  of  a  definite  shell,  yolk,  and 
clear  space,  little  trouble  is  experienced.  The  beginner  often 
diagnoses  vegetable  cells  as  uncinaria  eggs.  Those  foods 
that  are  "mealy"  when  cooked — like  beans,  peas,  potatoes, 
etc. — or  when  raw — like  apples,  etc. — furnish  the  greatest 
quantity  of  deceptive  vegetable  cells.  Many  a  time  we  have 
known  cells  diagnosed  as  hookworm  eggs  by  those  who  had 
seen  eggs  several  times  before,  notwithstanding  the  fact 
that  there  were  often  in  the  same  fluid  many  other  similar 
cells  not  at  all  egg-shaped  and  several  times  larger  or 
smaller  than  the  cells  diagnosed.  Vegetable  cells  are  irreg- 
ular in  outline,  shape,  and  size,  while  hookworm  eggs  are 
regular  in  these  particulars.     While  vegetable  cells  may  be 


170  HOOKWORM  DISEASE. 

found  strongly  resembling  hookworm  eggs,  there  will  be 
found  in  the  same  specimen,  and  usually  in  the  same  field, 
many  cells,  otherwise  like  the  one  in  question,  which  vary 
much  in  appearance  from  uncinaria  eggs.  The  segments  of 
the  yolk  9f  hookworm  eggs  are  made  up  of  very  fine  granu- 
lar matter,  whereas  the  chlorophyl  granules  of  vegetable 
cells  are  much  coarser.  Finally,  the  space  between  the 
yolk  and  shell  of  eggs  varies  much  at  different  points, 
whereas  the  outer  membrane  of  vegetable  cells  dips  in  over 
depressions  in  the  nuclear  material,  and  in  fact  makes  a 
covering  of  the  same  thickness  over  the  irregular  nuclear 
mass.  If  in  doubt  as  to  the  diagnosis  of  the  eggs,  they  may 
be  hatched  out  in  twenty-four  to  forty-eight  hours  and  the 
characteristic  larvae  looked  for.  To  this  end  some  feces 
may  be  placed  in  a  Petri  dish,  or  other  suitable  container, 
and  a  few  folds  of  filter  paper  stuck  down  in  it,  with  one 
end  extending  above  the  material.  This  serves  to  dry 
it  out  sufficiently,  and,  if  the  culture  is  kept  in  a  warm, 
shady  place,  hatching  soon  occurs;  or  the  feces  may  be 
mixed  with  one  or  more  parts  of  charcoal  or  sterile  sand,  in 
which  the  eggs  hatch  well.  This  should  be  moist,  but  not 
covered  with  water,  which  interferes  with  hatching.  The 
larvae  may  be  found  in  material  from  around  the  edges  of 
the  paper  or  dish,  but  after  a  few  days  will  crawl  up  on  the 
sides  and  cover  of  the  dish,  as  shown  by  Claude  A.  Smith 
in  his  excellent  experimental  work  on  this  subject.  He 
noted  little  grayish  smears,  consisting  of  numerous  larvae, 
on  the  sides  and  cover  of  the  culture  dish.  Larvae  of  im- 
cinaria  in  stools  are  not  found,  except  in  rare  instances, 
until  twenty-four  hours  or  longer  after  evacuation.  We 
have  often  found  them  in  feces,  always  associated  with 
large  numbers  of  eggs,  sent  by  mail — usually  specimens 
that  had  partly  dried  out.  It  must  be  remembered  that 
there  is  a  large  number  of  nematodes,  to  which  uncinaria 


DIAGNOSIS.  171 

belong,  the  rhabditiform  larvie  of  wliicli  can  not  be  easily 
differentiated  from  each  other. 

Special  Methods  for  Greater  Certainty  in  Finding  the  Eggs. 

Pepper's  method. — Pepper,  as  mentioned  above,  has 
called  attention  to  a  peculiarity  of  hookworm  eggs  which 
makes  it  possible  to  concentrate  them  considerably,  or  at 
least  to  get  rid  of  much  of  the  fecal  matter  and  thereby 
render  them  more  easily  found.  He  notes  that  when  mate- 
rial containing  eggs  is  allowed  to  settle  on  a  slide,  the  slide 
may  be  immersed  in  water  and  considerably  agitated  with- 
out the  eggs  coming  away,  though  the  slide  is  inverted  and 
all  the  feces  rinsed  off.  We  have  often  confirmed  his  find- 
ings. The  best  results  are  obtained  if  a  part  of  the  fecal 
material  is  removed  by  use  of  the  centrifuge  before  the 
slide  preparation  is  made.  Otherwise  the  method  is  often 
disappointing. 

Kiilz  recommends  Telemann  's  method  of  examining  feces. 
In  this,  equal  parts  of  ether  and  pure  hydrochloric  acid  are 
shaken  up  with  a  bit  of  feces,  filtered  through  gauze  and 
centrifugated.  The  fat  rises  to  the  top;  in  the  middle  layer 
are  the  solution  and  detritus,  and  at  the  bottom  insoluble 
remains  and  eggs.  We  have  found  the  method  admirable 
with  some  stools,  but  in  others  not  enough  solution  occurs 
to  permit  a  concentrated  layer  of  eggs  to  be  thrown  down. 

Sedimenting  the  feces  by  diluting  with  ten  or  more  times 
the  amount  of  water,  and  allowing  the  mixture  to  settle  for 
fifteen  minutes  or  longer  in  a  beaker,  test  tube,  or  conical 
glass,  assures  greater  success  than  examining  the  untreated 
feces.  The  eggs,  being  larger  and  heavier  than  many  of 
the  particles  making  up  the  fecal  mass,  settle  faster  and 
are  more  numerous  in  the  bottom  of  the  container.  Mate- 
rial may  now  be  taken  from  the  lower  layers  and  a  slide 
preparation  made  in  the  usual  manner.     By  repeating  the 


172  HUOKAVOim  DISEASE. 

sedimentation  several  times,  still  better  results  may  be 
obtained.  Concentration  of  the  eggs  with  the  centrifuge 
has  been  referred  to  by  Looss,  Claude  A.  Smith,  Ashford, 
King,  and  others.  Simply  centrifuging  the  diluted  feces 
does  not^  however,  give  the  best  results.  They  are  obtained 
only  when  the  most  careful  attention  is  paid  to  details 
which  we  believe  are  of  sufficient  importance  to  warrant 
thorough  consideration  here.  One-third  or  more  of  the  fecal 
mass  consists  of  bacteria  which  are  relatively  very  small 
compared  with  the  size  of  eggs.  They  have,  therefore,  a 
much  greater  surface  per  given  weight  than  eggs.  Most  of 
them  have  a  lower  specific  gravity  also.  Much  of  the  feces 
consists  of  food  particles  ranging  in  size  from  that  of  bac- 
teria up  to  coarse  macroscopic  particles.  Most  of  these 
food  particles  are  irregular  in  outline  and  shape,  making 
their  surface  per  given  weight  greater  than  that  of  the 
round,  oval  eggs.  The  specific  gravity  of  much  of  this 
material  is  less  than  that  of  eggs,  and  some  of  it  even  heav- 
ier. Feces  also  contain  variable  amounts  of  concretions — 
''fecal  sand,"  vegetable  cells,  crystals,  etc. — which  are  usu- 
ally heavier  than  eggs. 

Centrifuges. — These  are  of  three  kinds — hand,  water,  and 
electric.  The  speed  of  a  hand  centrifuge  varies  according 
to  the  rapidity  of  the  operator,  but  fairly  high  speeds  can 
be  obtained.  They  can  be  started  and  stopped  quickly. 
Water  centrifuges  do  not,  as  a  rule,  get  up  high  speed,  and 
they  start  and  stop  slowly.  Good  electric  centrifuges  run 
at  high  speed,  and  start  and  stop  quickly.  The  Purdy  cen- 
trifuge, made  by  Williams,  Browne,  and  Earle,  is  the  best 
we  know  for  this  purpose,  though  some  others  are  good. 
Satisfactory  work  for  practical  purposes  can  be  done  with 
a  good  hand  machine  that  costs  only  about  $8.00. 

The  feces  should  be  diluted  and  well  mixed  with  ten  or 
more  times  their  bulk  of  water.     This  should  be  strained 


DIAGNOSIS.  173 

through  two  or  three  layers  of  gauze  in  a  funnel  to  remove 
the  coarse  particles.  The  exact  length  of  time  necessary 
to  centrifuge,  in  order  to  throw  most  of  the  eggs  suspended 
in  water  to  the  bottom  of  the  tube,  should  be  determined  by 
experimenting  with  a  known  specimen  that  has  already 
been  washed  once  or  twice  and  contains  many  eggs.  This 
must  be  determined  with  the  particular  centrifuge  used. 
The  Purdy  centrifuge  used  by  us,  running  at  full  speed, 
throws  eggs  to  the  bottom  in  four  seconds.  "With  a  hand 
centrifuge  it  takes  considerably  longer,  depending  on  the 
speed  obtained.  As  the  first  diluted  feces  are  much  thicker 
than  the  washed  feces  and  eggs  on  which  the  working  time 
of  the  centrifuge  has  been  determined,  the  eggs  will  go 
down  somewhat  slower  the  first  time.  It  is,  therefore,  a 
good  plan  to  centrifuge  double  time  at  first.  If,  for  in- 
stance, the  working  time  of  the  centrifuge  is  four  seconds, 
the  first  centrifuging  should  be  eight  seconds.  This  throws 
to  the  bottom  most  things  heavier  and  larger  than  eggs — 
like  crystals,  sand,  large  vegetable  cells,  etc. — and  all  eggs 
present.  There  remain  suspended  in  the  supernatant  fluid 
nearly  all  bacteria  and  fine  particles,  and  many  coarse 
particles  lighter  and  more  irregularly  shaped  than  eggs. 
If  the  centrifuge  is  run  longer,  many  of  these  go  down, 
which  is,  of  course,  undesirable.  Pour  off  this  fluid,  and 
two-thirds,  and  often  much  more,  of  the  feces  are  removed 
by  this  washing.  Eefill  the  tube  to  about  three-fourths  its 
capacity,  shake  up  thoroughly,  and  centrifuge  again,  run- 
ning now  only  the  working  time  of  the  centrifuge.  It  is 
important  not  to  centrifuge  longer  than  the  working  time  of 
the  centrifuge,  as  many  fine  and  light  particles  would  other~~- 
wise  be  thrown  down.  Considerable  material  remains  sus- 
pended, and  may  be  removed  by  pouring  off  the  super- 
natant fluid.  Again  the  tube  is  filled,  shaken,  and  centri- 
fuged  a  proper  length  of  time,  and  generally  this  will  be 


174  HOOKWOEM  DISEASE. 

sufficient  for  jDractical  purposes.  A  part  or  all  the  sedi- 
ment is  removed  with  a  pipette,  spread  out  on  a  slide,  and 
examined  for  eggs.  It  consists  of  crystals,  sand,  and  heavy, 
coarse  food  particles,  and  eggs  if  present.  It  is  important 
to  remove  the  sediment  x)roijerly.  A  clean  pipette,  with 
the  finger  held  over  the  end  of  it,  is  carried  to  the  bottom 
of  the  tube.  Before  removing  the  finger  and  allowing  the 
sediment  to  run  in,  it  should  be  well  broken  loose  from  the 
bottom  of  the  tube  by  means  of  the  pipette.  Then  the 
finger  is  partially  removed,  and  a  part  or  all  the  sediment 
allowed  to  run  up  into  the  pipette.  Part  or  all  this  is 
spread  on  a  slide  and  examined  as  usual.  A  worker  accus- 
tomed to  this  procedure  is  able  to  wash,  centrifuge  several 
times,  and  get  the  sediment  of  a  specimen  on  a  slide  ready 
for  examination  within  four  or  five  mmutes.  The  examina- 
tion takes  about  the  same  time  as  is  required  to  examine 
an  ordinary  preparation  of  feces  of  the  same  size,  but  usu- 
ally all  the  sediment  may  be  placed  on  one  slide,  and  one 
slide  is,  therefore,  all  that  it  is  necessary  to  examine.  A 
mechanical  stage  enables  one  more  thoroughly  to  go  over 
the  slide.  A  large  amount  of  the  sediment  can  be  examined 
if  Pepper's  technic  is  now  used.  After  allowing  the  thick 
smear  to  settle  well,  the  slide  is  immersed  in  a  beaker  or 
glass  of  water.  Uncinaria  eggs  remain,  but  most  other 
things  wash  off.  One  serious  objection  to  following  this 
technic  is  that,  while  looking  for  hookworm  eggs,  we  also 
want  to  find  any  other  eggs  present.  No  other  eggs  we 
know  of  stick  to  the  slide  like  hookworm  eggs.  This  pro- 
cedure cannot,  therefore,  be  recommended  for  general  work. 
Great  care  must  be  exercised  to  clean  the  centrifuge  tubes 
before  using  them  after  they  have  had  eggs  in  them.  A 
proper  centrifuge  tube  brush  is  serviceable. 

The  method  of  centrifuging  described  above  is  all  that  is 
necessary  for  ordinary  practical  purposes,  and,  if  properly 


DIAGNOSIS. 


175 


done,  permits  the  finding  of  eggs  when  less  than  half  a 
dozen  laying  females  are  present,  and  often  when  only  one 
is  present.  It  is  of  additional  service  because  it  permits  at 
the  same  time  diagnosis  of  infections  with  many  other 
worms  by  which  much  fewer  eggs  are  laid,  such  as  the 
tenias,  oxyuris,  bothriocephalus,  etc.  Bass  found  that  he 
could  still  further  concentrate  the  eggs  by  washing  with 
calcium  chloride  solution  after  washing  with  water.     The 


Fig.    46.     Microscopic    appearance    of    feces,    sliowing    poorly    one    egg    in 
center. 


specific  gravity  of  fresh  hookworm  eggs  is  near  1,100.  This 
usually  increases  as  the  specimen  gets  old.  A  solution  of 
calcium  chloride  having  a  specific  gravity  of  1,050  will  sus- 
pend considerable  of  the  sediment,  though  the  eggs  still 
readily  go  to  the  bottom.  By  washing  with  this  solution 
two  or  three  times  after  washing  with  water,  much  material 
not  removed  with  the  water  can  be  removed.  If  still  better 
results  are  desired,  the  crystals  and  very  heavy  things  can 


176 


HOOKWORM  DISEASE. 


be  removed  by  washing  with  a  solution  of  calcium  chloride 
of  1,250  specific  gravity,  in  which  most  of  them  go  down, 
but  hookworm  eggs  float.  After  centrifuging,  the  super- 
natant fluid  containing  the  eggs  is  poured  off  and  appropri- 
ately diluted  with  water,  and  the  eggs  again  thrown  to  the 
bottom,  from  where  they  are  easily  taken  up.  This  calcium 
chloride  washing  is  necessaryonlywhen  very  great  accuracy 


M 

^^^ 

P9 

M 

^^^ 

P^^Ha'^a^^^^^B)  1 

m 

^^^ 

^m 

^^^B^^^^k3 

^^^^^^ 

^^m 

He^ 

^!^3K^Sl^fHil 

i^i^H 

Fig.  47.     Preparation  made  by  Bass'  method  from  feces  shown  in  Fig-.  46. 
Appear  about  as  large  as  they  do  with  1/6  objective  and  2-inch  eyepiece. 

is  desired,  or  when  it  is  desired  to  collect  eggs  absolutely 
free  from  fecal  material  for  scientific  purposes.  Solutions 
of  calcium  chloride  of  several  different  strengths  should  be 
employed  for  this  purpose,  and  much  is  also  gained  by  keep- 
ing the  patient  on  a  wholly  digestible  diet.  Bass  found  that 
with  this  technic  he  was  able  to  recover  96  percent  of  one 
thousand  eggs  placed  in  one  ounce  of  feces,  94  percent  of 
one  hundred  eggri  in  the  ^ame  amount,  and  60  percent  of 
ten  eggs  in  one  ounce.     The  value  of  the  centrifuge  is  shown 


DIAGNOSIS.  177 

by  the  work  of  Gage  and  Bass.  They  examined  the  feces  of 
315  university  students.  One  to  25  slides  were  examined 
in  the  ordinary  way,  and  104  cases  were  found  infected  with 
some  intestinal  parasite,  79  of  them  being  hookworms.  The 
specimens  found  negative  by  the  ordinary  technic  were  cen- 
trifuged,  either  using  water  only  or  water  and  calcium 
chloride  solution,  as  described.  By  this  method  38  ad- 
ditional hookworm  cases  were  found.  Of  the  entire  104 
cases  of  intestinal  parasite  infection  47  percent  were  found 
by  the  usual  technic,  and  53  percent  were  missed  until  the 
centrifuge  technic  was  employed.  It  is  to  be  emphasized 
that  most  of  this  series  of  cases  were  mild  cases  of  uncinari- 
asis, or  infection  with  other  worms  that  lay  fewer  eggs  than 
uncinaria.  Gage  and  Bass  conclude  after  this  extensive  ex- 
perience that,  for  all  practical  purposes,  washing  with  water 
alone  is  all  that  is  necessary,  and  that  the  washing  with 
calcium  chloride  solution  is  unnecessary,  except  for  special 
purposes. 

As  to  whether  it  is  necessary  to  use  the  centrifuge  in 
every  case,  we  would  say  that  it  is  not  in  the  ordinary  diag- 
nosis and  treatment  of  hookworm  disease,  but  that  it  is 
necessary  for  the  recognition  of  many  cases  of  mild  worm 
infection.  The  time  consumed,  ten  to  fifteen  minutes,  is  not 
as  great  as  that  required  to  make  a  much  less  reliable  ex- 
amination by  the  ordinary  technic,  and  the  satisfaction  de- 
rived from  being  certain  that  no  eggs  are  present  is  worth 
the  effort. 

Diagnosis  by  Examining  Stools  for  Worms  after  Treatment. 

Either  thymol  or  beta-naphtol  may  be  given  for  this  pur- 
pose, and,  though  usually  recommended  in  smaller  doses  for 
diagnosis  than  for  treatment,  we  believe  that,  unless  special 
contraindications  exist,  the  full  regulation  dose  should  be 
given,  preceded  and  followed  by  the  same  purgation  and 


178  HOOKWOEM  DISEASE. 

starvation  as  if  a  well-marked  case  was  being  treated.  All 
feces  passed  during  the  first  twelve  to  twenty-four  hours 
after  the  last  purge  should  be  examined  by  washing,  as  de- 
scribed by  Dr.  Stiles.  They  are  stirred  in  a  bucket  or  other 
suitable  vessel  with  water,  after  which  the  mixture  is  al- 
lowed to  settle  a  minute  or  two.  The  supernatant  fluid  is 
poured  off  and  the  sediment  rewashed  several  times.  After 
washing  thoroughly,  the  residue  is  placed  in  a  flat  dish  or 
vessel  with  water  in  it,  and  the  worms  searched  for.  A 
glass  dish  placed  over  a  black  surface,  or  one  painted  black, 
makes  the  identification  of  the  worms  easier.  The  worms 
may  be  collected  with  a  pair  of  tweezers.  They  are  about 
the  thickness  of  a  common  brass  pin,  from  three-eighths  of 
an  inch  (shortest  males)  to  five-eighths  of  an  inch  (longest 
females)  in  length,  and  are  white  or  gray  in  color,  according 
to  the  amount  of  food  and  eggs  they  contain.  A  complete 
description  of  the  worms  is  given  in  the  chapter  on  zoology. 
It  should  be  said  here  that  the  worms  are  not  likely  to  be 
found  in  the  stools,  except  after  treatment.  The  history 
often  related  by  people  that  they  saw  hookworms  in  their 
stools  usually  means  that  they  have  mistaken  some  other 
worm  or  food  particles  for  hookworms.  In  fact,  the  worms 
are  often  not  found  even  when  many  are  present,  unless 
they  are  properly  looked  for  and  with  great  care. 

Blotting  Paper  Test. 

Stiles  has  found  that  in  a  large  proportion  of  medium  or 
severe  cases  of  uncinariasis  this  test  is  positive.  It  is  made 
by  placing  on  a  piece  of  white  blotting  paper,  or  other  soft 
white  paper,  some  fresh  feces.  In  about  fifteen  minutes 
these  are  removed,  and  when  the  test  is  positive  the  paper 
will  show  a  red  or  reddish  brown  blot  where  the  feces  had 
been.  Though  of  service  in  some  cases,  the  test  can  not  be 
recommended  for  general  use,  because  of  the  many  other 


DIAGNOSIS.  179 

sources  of  positive  tests  besides  hookworm  disease,  such  as 
other  hemorrhages,  vegetable  coloring  matter,  etc.  We 
have  found  it  positive,  however,  in  several  severe  cases  of 
uncinariasis. 

The  Eosinophile  Count  in  Diagnosis. 

The  importance  of  the  eosinophile  leucocyte  count  in  the 
diagnosis  of  hookworm  disease  has  been  emphasized  by 
Boycott  and  Haldane,  and  under  certain  conditions  may  be 
of  value.  They  found  of  one  hundred  and  forty-eight  men 
infected  with  ankylostoma  duodenalis  94  percent  had  over  8 
percent  of  eosinophiles,  and  only  3  1/2  percent  had  less  than 
5  percent  of  eosinophiles.  In  eight  hundred  noninfected 
miners  there  were  only  seven  cases  of  eosinophilia.  The 
feces  of  one  of  those  were  not  examined.  Two  showed 
ascaris  eggs,  and  the  other  four  showed  trichocephalus  dis- 
par  eggs.  They  especially  recommend  the  eosinophile 
count  because  of  the  rapidity  with  which  it  can  be  made. 
They  examined  one  hundred  and  eighty-three  films  in  four 
days. 

They  themselves  point  out  that  the  method  is  most  useful 
only  in  regions  where  other  causes  of  eosinophilia  are  rare. 
They  say  "this  method  could  not  be  employed  with  success, 
for  example,  with  an  ordinary  Swiss  population,  where 
ascaris  is  a  frequent  cause  of  a  high  grade  of  eosinophilia; 
still  less  in  the  tropics,  where  natives  have  more  than  one 
cause  of  eosinophilia  in  their  persons  besides  ankylostoma. 
No  suggestion  has  ever  been  made  by  us,  however,  that  it 
should  be  used  under  these  circumstances,  nor  has  it  been 
proposed  that  the  examination  of  blood  films  should  replace 
the  search  for  eggs  in  the  feces  in  persons  in  whom  a  prima- 
facie  case  for  the  presence  of  ankylostomiasis  has  been 
made  out.  The  ultimate  diagnosis,  which  is  preliminary 
to  treatment,  must  rest  on  the  examination  of  the  feces.     A 


180  HOOKWOEM  DISEASE. 

IDreliminary  examination  of  the  blood  will,  however,  save  a 
great  deal  of  trouble  in  cases,  as  in  English  miners,  where 
other  causes  of  eosinophilia  are  practically  absent." 

In  six  hundred  and  ninety-three  cases  of  hookworm  in- 
fection in  ^various  degrees  of  which  we  have  record  of  the 
blood  examination  the  eosinoijhile  count  was  5  percent  or 
over  in  two  hundred  and  twelve  and  below  5  percent  in  four 
hundred  and  eighty-one.  The  highest  count  was  34  per- 
cent and  the  lowest  1  5  percent.  The  average  for  the 
entire'  number  was  4  1.  8  percent.  The  average  for  two 
hundred  selected  lowest  count  cases  was  2  1/3  percent.  It 
should  be  stated  that  the  majority  of  these  cases  were  mild 
infections,  and  indeed  many  of  them  so  mild  as  to  require 
the  use  of  the  centrifuge  before  ova  were  found.  In  four 
hundred  and  four  well  people,  whose  blood  and  feces  were 
examined  and  no  uncinaria  or  other  eggs  found,  the  eosino- 
philes  averaged  2  7/10  percent.  The  highest  was  17  per- 
cent and  the  lowest  none  in  a  five  hundred  cell  count. 
Above  5  percent  was  recorded  in  thirty-four  instances. 
Many  cases  of  severe  uncinariasis  have  not  more  than  the 
normal  count,  as  pointed  out  l)y  Ashford  and  King,  and  this 
is  true  in  almost  all  cases  shortly  before  death.  It  is  cer- 
tain, however,  that  most  moderate  or  severe  cases  of  hook- 
worm infection  have  counts  above  the  normal.  From  the 
above  and  our  own  exjDerience  we  would  conclude  that  the 
chief  value  of  the  eosinophile  count  in  the  diagnosis  of 
hookworm  disease  lies  in  the  suggestion  a  high  count  makes 
to  examine  the  feces  when  the  disease  has  not  otherwise 
been  suspected.  Eosinophilia  is  present  in  so  many  hook- 
worm and  other  worm  infections  that  we  lielieve  the  feces 
should  always  be  examined  when  high  counts  are  obtained. 

In  this  connection  it  may  be  well  to  call  attention  to  the 
fact  that  a  count  of  one  hundred  cells  does  not  give  a  re- 
liable estimate  of  the  percentage  of  eosinophiles  or  any 


DIAGNOSIS.  181 

other  cells  found  in  small  numbers.  It  is  necessary  to  count 
at  least  three  hundred  cells,  and  preferably  five  hundred. 
Much  speed  can  be  gained  b}^  taking  only  the  total  leu- 
cocytes and  the  eosiuophiles.  Counting  by  twos,  threes, 
or  fives,  instead  of  by  ones,  also  saves  time.  For  speed  the 
thickest  part  of  a  spread,  where  the  cells  can  be  differen- 
tiated, is  best. 


CHAPTER  VIII. 

PROGNOSIS. 

The  prognosis  of  hookworm  infection  varies  within  wide 
extremes,  depending  on  several  factors,  such  as  number  of 
worms,  age  and  constitution  of  the  patient,  possibility  of 
getting  proper  food,  and  especially  of  receiving  proper  and 
timely  treatment. 

If  the  worms  are  few  and  the  individual  well  nourished, 
hookworm  disease  does  not  always  develop.  The  subject 
remains  a  carrier.  Though  not  ill  subjectively,  he  is,  how- 
ever, in  a  pathologic  condition,  and  often  shows,  on  careful 
examination,  not  only  ova  of  the  parasites  in  the  stools,  but 
also  slight  loss  of  weight  in  proportion  to  his  age,  slight 
lowering  of  the  blood-coloring  matter  and  red  blood  cor- 
puscles, and  eosinophilia.  We  believe  these  slight  abnor- 
malities are  not  without  importance.  If  the  subject  is  able 
to  eat,  digest,  and  assimilate  enough  proper  food,  and  to  live 
comfortably,  he  may  be  able  to  keep  abreast  of  his  contem- 
poraries in  school  and  college,  and  to  hold  his  own  at  work, 
or  in  business  or  a  profession.  By  six  or  seven  years  after 
his  last  infection,  in  most  cases,  he  is  free  from  parasites, 
these  having  died  of  old  age.  Under  favorable  circum- 
stances the  subject  now  recovers  completely.  In  some  cases, 
however,  we  suspect  that  the  drain,  though  slight,  caused 
by  the  parasites  will  have  damaged  the  host,  and  that  neu- 
rasthenia, or  vascular  or  cardiac  disease,  may  come  on  by 
reason  of  the  excessive  calls  on  the  energy  of  the  latter. 
For  this  reason,  as  well  as  for  prophylactic  purposes,  all 
hookworm  carriers  should  be  sought  out  and  treated.     If 

182 


PROGNOSIS. 


183 


they  are  exposed  to  reinfection,  the  risk  of  permanent,  even 
though  slight,  damage  is  greater. 

It  is  doubtful  whether  true  immunity  occurs  in  Caucas- 
ians. Mild  cases  may  go  on  for  years,  the  worms  gradually 
undergoing  senile  changes,  and  therefore  less  potent  for  ill. 

In  moderate  infections,  among  poor  people,  a  lowering  of 
physical  and  mental  and  moral  strength  occurs.  School 
children  so  affected  may  not  be  able  to  accomplish  more 
than  60  percent  of  required  work. 

The  worst  cases  are  those  in  which  there  is  a  heavy  infec- 
tion, with  from  one  to  many  thousand  worms.     Even  in 
well-to-do    subjects   these   become    severely    affected,    but 
among  the  underfed  or  the  overworked  the  results  are  most 
serious.     Either  the  patient  becomes  rapidly  anemic,  with 
digestive  disorders,  sometimes  severe  diarrhea  with  hemor- 
rhages, anasarca,  and  extreme  debility,  or  the  conditions 
may  be  more  chronic.    Indolence  and  weakness  lead  to  care- 
less habits.     Reinfection  occurs  from  time  to  time.     Often 
a  whole  family  becomes  affected  more  or  less  seriously. 
The  wage  earners  lose  part,  or  later  all,  of  their  income,  the 
food  supply  becomes  more  scanty,  and  a  vicious  circle  of 
poverty,  weakness,  and  disease  is  established.     Often  doc- 
tors are  far  away,  or  even  not  accessible  at  all,  and  a  whole 
family  may  be  exterminated  before  the  youngest  children 
are  half  grown.    Formerly  these  cases  were  supposed  to  die 
of  pernicious  malaria,  of  nephritis,  and  in  some  countries  of 
beriberi.    We  strongly  suspect,  with  many  other  southern 
physicians,  that  many  cases  in  negroes,  ending  fatally  and 
supposed  to  be  tuberculosis,  are  undiagnosed  cases  of  hook- 
worm disease.     The  difficulty  of  getting  a  clear  history  in 
negroes,  the  rarity  of  physical  diagnosis  and  sputum  exami- 
nation, and  the  similarity  of  the  late  symptoms  in  the  dis- 
ease make  the  confusion  a  very  natural  one. 


184  hookworjm  disease. 

Mortality. 

The  mortality  of  hookworm  disease  in  America  can  not 
yet  be  accnrately  stated.  The  disease  has  not  been  known 
long  enough,  and  the  diagnosis  is  not  attempted  often 
enough,  \o  furnish  data  of  value.  In  Porto  Rico  Ashford 
and  King  estimated  the  death  rate  before  systematic  treat- 
ment was  begun  at  30  percent,  which  was  probably  not  too 
high.  In  Egypt,  among  cases  treated,  Sandwith  thinks 
89.5  percent  are  cured  or  greatly  relieved,  2.5  are  un- 
relieved, and  8  percent  die.  One-third  of  the  latter  are  first 
seen  moribund,  another  third  die  of  various  complicating 
diseases,  and  the  remaining  third  of  hookworm  disease. 

In  the  prognosis  of  a  given  case  the  most  useful  guides 
are  the  general  condition  and  the  condition  of  the  most  im- 
portant organs,  the  probable  number  of  worms  as  shown 
by  the  fecal  examination,  and  the  possibility  of  proper  treat- 
ment, which  often  depends  upon  the  financial  condition  of 
the  patient.  ' ' The  destruction  of  the  poor  is  their  poverty" 
applies  with  particular  force  in  hookworm  countries. 

Of  other  points,  eosinophilia  has  some  value.  In  severe 
cases,  if  present,  it  is  usually  a  sign  that  the  disease  has  not 
gone  on  to  complete  exhaustion  of  the  blood-forming  organs. 
In  mild  cases  it  often  indicates  periods  of  relative  well- 
being.  Prof.  Fiilleborn,  of  Hamburg,  who  had  an  experi- 
mental infection,  told  us  his  eosinophiles  were  always 
higher  when  he  was  feeling  best. 

The  Porto  Rico  Commission,  in  1904,  wrote  (page  84) : 

''The  chief  interest  centered  around  the  eosinophiles. 
There  is  no  doubt  that  the  following  conclusions  may  be 
drawn  with  safety  (conclusions  which,  by  the  way,  were 
suggested  in  the  report  of  the  Ponce  cases  in  1903) : 

"1.  Very  severe  chronic  cases,  with  poor  resisting  power 
and    exhausted   blood-making    organs,    have   little    or   no 


PROGNOSIS.  185 

eosinopliilia.  Leiclitenstern's  remarkable  case  of  72  per- 
cent eosinophiles  just  before  death  does  not  negative 
this  view.  We  had  a  case  which  died  in  coma,  possibly  due 
to  cerebral  effusion.  This  child  was  admitted  with  6.4  per- 
cent eosinophiles  and  died  with  20.8  percent. 

"2.  A  rise  in  eosinophiles  is  of  good  prognostic  import. 
Especially  is  this  true  of  those  who,  admitted  to  treatment 
with  conditions  described  under  1,  begin  to  show  higher 
and  higher  eosinophile  counts.  There  are  such  cases,  not 
explicable  to  us,  where,  in  spite  of  a  lack  of  rise  in  these 
cells,  improvement  does  take  place.  It  may  be  rather  rajoid, 
but  is  generally  very  slow. 

"3.  If  very  severe  cases,  presenting  little  or  no  eosino- 
pliilia, [have  a]  fall  in  their  eosinophile  count,  the  prognosis 
is  not  generally  good. 

"In  general,  good  resistance  to  the  toxin  of  uncinaria  is 
expressed  by  eosinopliilia.  Our  special  cases,  being  nearly 
all  severe,  gave  an  average  of  10.8  percent  eosinophiles  be- 
fore any  treatment  was  begun,  and  the  ultimate  percentage 
of  these  cells,  after  all  treatment  had  been  concluded,  was 
13.2.  As  forty-two  of  the  sixty-one  were  completely  cured 
at  that  time,  and  fifteen  were  nearly  so,  it  is  clearly  seen 
that  the  number  of  uncinarise,  per  se  has  nothing  to  do  with 
eosinopliilia  directly.  As  to  the  oft  cited  remark  that  eosino- 
phil ia  and  Charcot-Leyden  crystals  increase  and  fall  to- 
gether, there  are  cases  which  fail  to  show  such  relation. 

"The  eosinophiles  behave  in  a  most  extraordinary  way 
in  the  course  of  cure.  There  seems  to  be  a  general  rise  to  a 
certain  percentage,  varying  according  to  the  individual, 
after  which  a  fall  to  normal  takes  place.  This  fall  to 
normal  may  occur  before  the  patient  reaches  a  normal 
hemoglobin  percentage,  or  may  be  delayed  until  some  time 
after  cure.  In  this  course  of  rise  and  fall,  great  undula- 
tions may  take  place  in  the  curve,  which  as  yet  seem  to  be 
difficult  to  explain. 


186  HOOKWORM  DISEASE. 

' '  Some  very  pertinent  questions  arise  in  consideration  of 
the  question  of  eosinophilia: 

*'l.  Is  it  an  evidence  of  blood  regeneration,  of  increased 
activity  of  blood-making  organs? 

"2.  \s  it  that  eosinophiles  are  directly  concerned  in  the 
defense  of  the  organism  against  the  toxin? 

"There  are  many  other  theories  concerning  eosinophilia 
in  general — for  instance,  that  of  Weiss,  who,  Ewing  says, 
maintains  'that  local  eosinophilia  tends  to  occur  where 
there  is  extensive  extravasation  of  blood,  the  derivatives  of 
hemoglobin  being  absorbed  by  the  polynnclear  cells  and 
deposited  in  the  form  of  eosinophile  granules.'  " 

Among  other  elements  in  prognosis,  pregnancy  is  an  un- 
favorable one.  Abortion  is  likely  to  occur,  and  it  as  well 
as  birth  at  term  may  be  fatal  in  anemic  patients.  Lacta- 
tion is  imperfect  in  hookworm  patients,  but  promptly  im- 
proves under  thymol  treatment.  The  offspring  of  un- 
treated hookworm  patients  are  likely  to  be  poorly  devel- 
oped and  marantic. 

While  the  most  severe  cases  are  seen  in  early  life,  the 
disease  is  sometimes  severe  in  cases  that  develop  after  60. 
All  complications  that  contraindicate  treatment  render  the 
prognosis  worse. 

The  effect  of  hookworm  disease  on  duration  of  life  is  very 
important.  Old  people  in  the  rural  districts  of  hookworm 
countries  seem  less  numerous  than  they  are  in  cities,  with 
their  greater  exposure  to  numerous  adverse  conditions. 
The  Porto  Rico  Commission  confirms  this  by  stating  that  in 
Porto  Rico,  though  there  are  more  children  in  proportion 
to  adults  than  in  any  other  state,  except  South  Carolina, 
those  over  60  years  are  forty  to  the  thousand,  as  compared 
with  sixty-two  to  the  thousand  in  the  United  States  in 
general. 


PROGNOSIS.  187 

Intercurrent  Diseases  and  Complications. 

Like  all  conditions  with  anemia,  hookworm  disease  is 
likely  to  be  associated  with  many  other  diseases.  Some  of 
them  are  assisted  by  the  anemia,  and  some  are  due  to  the  in- 
testinal derangements  and  the  perversions  of  appetite.  The 
following  are  especially  frequent:  gastritis,  dilatation  of 
the  stomach,  enterocolitis,  amebic  and  bacillary  dysentery, 
edema  of  the  lungs,  neurasthenia,  and  nephritis.  The  latter 
is  very  common  in  advanced  cases.  Syphilis  and  tubercu- 
losis are  not  especially  frequent,  but  are  likely  to  be  severe, 
in  hookworm  subjects.  Rheumatic  pains  are  not  uncom- 
mon. Ashford  and  King  recovered  from  the  blood  of  such 
cases  a  bacillus,  which,  however,  they  also  found  in  other 
diseases.  Among  other  diseases  frequently  encountered  in 
histories  of  hookworm  subjects  are:  tonsilitis,  laryngitis, 
pneumonia,  paresis,  hemiplegia,  jaundice,  ulcer  of  the 
stomach,  conjunctivitis  and  trachoma,  renal  colic,  pellagra, 
and  elephantiasis.  The  last  two  named  occur  in  endemic 
areas,  and  the  relation  is  only  an  assisting  one. 

As  regards  pneumonia,  Gregorson  reports  some  interest- 
ing facts  from  Assam,  where  the  tea-gardeners  were  for- 
merly very  severely  affected  with  hookworm.  Pneumonia 
was  also  very  frequent,  but,  as  the  hookworm  disease  be- 
came less  frequent  under  sanitation  and  treatment,  there 
was  a  notable  fall  in  the  incidence  of  pneumonia.  The  fre- 
quency and  severity  of  pneumonia  in  the  southern  states  of 
America  have  often  been  noted,  and  no  good  explanation 
for  it  has  been  advanced.  It  can  not  be  doubted  that  the 
effects  of  hookworm  infection  lower  the  resi^stance,  so  that 
depressing  diseases  of  all  kinds  are  more  difficult  to  with- 
stand. Moreover,  the  hookworm  anemia  lowers  the  amount 
of  oxygen-carrying  blood,  while  lack  of  oxygen  in  pneu- 
monia increases  the  need. 


188  HOOKWORM  DISEASE. 

Other  Parasites. 

It  is  to  be  expected  that  hookworm  subjects  slioiild  often 
liarbor  otlier  intestinal  parasites  as  well  as  others,  as  they 
usuallj^  live  where  parasites  of  all  kinds  are  frequent. 
Many  of  the  other  entozoa,  though  not  all,  are  expelled 
with  hookworms  after  treatment.  The  following  may  be 
named:  ascaris  lumbricoides  and  ascaris  caninum;  bil- 
harzia,  trichinella,  strongyloides,  balantidium,  oxyuris,  dip- 
logonoporus  grandis,  amebse,  fasciola  hepatica,  tenia  sagi- 
nata  and  tenia  solium,  aud  filaria. 

Among  the  most  frequent  sequels  in  severe  cases  are:  dis- 
eases of  the  heart,  liver,  and  kidneys,  endocarditis  and  arte- 
riosclerosis, severe  anemia,  intestinal  indigestion  due  to  the 
destruction  of  the  mucous  membrane  by  bites  and  infection, 
and  ulceration  of  the  intestine. 

Among  rare  results  are  perforation  and  stricture  of  the 
gut.  .      , 

It  should  be  clearly  understood  that  the  prognosis  in 
hookworm  disease  is  favorable  in  proportion  to  the  prompt- 
ness and  the  completeness  of  treatment. 

In  rare  cases  the  condition  is  such  that  treatment  can  not 
be  borne,  or  the  patient  is  too  ill  to  recover  even  if  the 
worms  are  removed. 


CHAPTER  IX. 

PROPHYLAXIS. 

"In  the  imiversal  treatment  of  persons  affected  lies  the 
secret  of  successful  opposition  to  uncinariasis."  (Porto 
Rico  Commission.) 

Hookworm  disease  is  theoretically  one  of  the  easiest  to 
prevent.  Its  cause  is  known — unlike  the  causes  of  the 
eruptive  fevers,  that  still  remain  as  tests  of  hygienic  ef- 
ficiency. All  the  vital  characteristics  of  the  parasite  are 
understood;  it  has  no  secondary  host,  like  the  tapeworms, 
that  spend  part  of  their  cycle  in  animals  widely  used  as 
food;  it  is  not  easily  taken  with  drinking  water  or  milk,  like 
the  germ  of  typhoid  fever;  it  is  not  carried,  to  any  serious 
extent  at  least,  by  flies  or  other  insects,  nor  by  the  wind. 
In  a  word,  it  does  not  come  to  man — man  goes  to  it. 

Practically  it  is  one  of  the  most  difficult  diseases  to  pre- 
vent or  eradicate  on  account  of  its  wide  extent,  its  intensity 
in  favorable  localities,  the  enormous  reproductive  power 
of  the  adult  worm,  the  rapid  development  of  the  ova  to  the 
infecting  stage,  and  the  commonest  method,  until  recently 
unsuspected,  of  infection.  The  very  fact  that  the  skin  in- 
fection has  not  been  known  longer  may  be  the  main  reason 
why  the  prophylaxis  in  the  past  has  been  so  difficult.  Wider 
recognition  of  it  may  bring  about  a  greater  change.  An- 
other cause  of  difficulty  in  prevention  depends  upon  the  fact 
that  the  sources  of  infection,  their  number,  and  danger  re- 
sult directly  from  careless  or  filthy  habits.  These,  too,  seem 
almost  ineradicable,  but  may  be  much  more  amenable  to 
education  than  they  now  appear. 

The  magnitude  of  the  task  of  prevention  appears  from  the 

189 


190  HOOKWORM  DISEASE. 

statistics  given  in  Chapter  II.  In  hookworm  localities 
practically  all  children  and  many  adults  have  the  disease, 
reinfection  keeping  it  up  much  longer  than  the  usual  life- 
time of  each  worm.  Probably  most  rural  negroes  also  are 
affected  in  all  parts  of  the  world,  but  often  do  not  show 
symptoms.  So  the  two  classes  of  the  population  most  re- 
gardless of  cleanliness  can  do  most  harm  by  their  lack  of 
that  virtue. 

The  problem  of  prophylaxis  involves  the  following  essen- 
tial elements: 

1.  Stopping  the  danger  of  infection  by  exterminating  the 
mature  worms  in  the  bodies  of  human  beings  in  order  to 
check  the  supply  of  eggs  at  the  source. 

2.  Preventing  the  growth  and  existence  of  larvae  in  the 
places  where  they  develop. 

3.  Preventing  infection  by  larvae  that  have  developed, 
notwithstanding  the  efforts  mentioned  under  1  and  2. 

1.  Extermination  of  the  mature  worms. — The  first  need 
for  the  prevention  of  hookworm  disease  is  to  stop  it  in  those 
already  affected — hookworm  patients.  This  is  a  task  that 
will  naturally  fall  upon  the  physician.  When  the  disease 
was  unrecognized,  cure  was  out  of  the  question.  Now  that 
the  condition  is  so  clearly  realized  that  the  symptoms  are 
often  recognized  even  by  laymen,  and  the  microscopic  diag- 
nosis is  easy  to  make,  we  can  expect  a  distinct  advance  in 
the  successful  treatment  of  these  important  cases  as  soon 
as  the  people  appreciate  the  danger  now  existing.  Accu- 
rate recognition  of  the  sick,  careful  treatment,  controlled  by 
examination  of  the  feces,  and  repeated  until  perfect,  will 
lessen  the  supply  of  ova  to  a  great  extent. 

But  not  altogether.  There  remains  the  great  and  im- 
portant class  of  hookworm  carriers — of  people  either  with 
no  symptoms,  or  with  symptoms  so  mild  as  to  go  unnoticed, 
but  with  from  a  few  to  a  couple  of  hundred  worms,  most  of 


PROPHYLAXIS.  191 

which  will  live  for  several  years,  laying  eggs  in  large  num- 
bers all  the  time,  and,  in  hookworm  localities,  keeping  rein- 
fected for  longer  periods.  These  people  are  all  the  more 
dangerous  because  they  are  not  supposed  to  be  sick,  just 
as  a  child  with  mild  scarlet  fever  or  diphtheria  is  more 
likely  seriously  to  infect  a  whole  school  or  community  than 
one  with  a  severe  case  that  will  be  promptly  isolated.  The 
hookworm  carriers  require  methods  of  hygienic  treatment 
not  necessary  for  cases  of  illness  of  obvious  kinds.  As  they 
are  not  indisposed,  they  will  not  consult  physicians;  but,  as 
they  are  menaces  to  the  health  of  the  community,  it  is  evi- 
dently the  duty  and  within  the  power  of  the  health  authori- 
ties to  search  them  out  and  deal  with  them  as  if  they  were 
sick,  and  to  see  they  become  harmless.  This  not  only  in- 
volves a  new  exercise  of  the  police  power  already  possessed 
by  boards  of  health,  which  seem  arbitrary  to  those  who  have 
barbarous  ideas  of  personal  liberty,  but 'is  a  task  beyond 
the  physical  ability  of  the  usual  health  administration  as 
now  constituted.  Hookworm  eradication  requires  an  ade- 
quate sanitary  organization,  which  would  bring  many  bene- 
fits besides  checking  hookworm  infection. 

It  would  be  necessary  to  make  periodic  examinations  of 
all  persons  living  in  localities  and  under  conditions  favor- 
able to  the  existence  of  hookworm  larvae,  and  to  keep 
records  of  all  of  these;  to  examine  all  newcomers,  to  see  that 
treatment  is  carried  out  to  a  successful  degree,  and  that 
patients  or  carriers  once  cured  do  not  become  reinfected,  or, 
if  they  do,  to  treat  them  again.  The  same  authorities 
should  organize  education  in  regard  to  hookworm  disease. 

In  localities  where  the  population  is  known  to  the  health 
officers — as  in  camps,  mines,  tunnel  or  canal  workings — the 
inspection  and  treatment  of  newcomers  could  be  easily  ac- 
complished. In  mills  and  factories,  employers  would  find  it 
to  their  advantage  to  have  the  hands  periodically  examined 


192  HOOKWOEM  DISEASE. 

aucl  treated.  A  gain  of  20  to  40  percent  of  hemoglobin,  with 
a  corresponding  gain  of  energy,  would  result.  In  towns, 
villages,  or  country  districts  methods  of  surveillance  that 
have  not  as  yet  been  applied  in  America  would  be  neces- 
sary. As  regards  patients,  carriers,  and  suspects,  there 
should  always  be  close  and  cordial  co-operation  between 
practicing  physicians  and  health  authorities. 

The  value  of  accurate  and  careful  methods  under  natural 
disadvantages  has  been  shown  in  many  places  within  the 
last  few  years,  not  only  in  the  Westphalian,  Belgian,  and 
French  coal  mines,  but  especially  in  the  island  of  Porto 
Rico,  where  the  work  of  the  ' '  Anemia  Commission, ' '  organ- 
ized by  Ashford  and  King,  has  furnished  a  model  of  efficient 
and  economic  administration. 

2.  Prevention  of  soil  infection. — The  next  essential  is  the 
prevention  of  soil  infection.  In  all  countries  about  the 
dwelling  houses,  and  in  all  mines,  tunnels,  or  similar  works 
where  men  handle  earth,  soil  pollution  from  lack  of  care 
in  the  disposal  of  feces  is  the  rule.  If  people  with  hook- 
worms are  present,  the  soil  becomes  infected,  and,  if  the  soil 
and  climatic  conditions  are  favorable,  the  larvge  develop. 
The  Porto  Rico  Commission  (1904)  expresses  the  matter 
clearly: 

''Uncinariasis  is  pre-eminently  a  filth  disease.  The  only 
means  of  infecting  the  soil  is  by  evacuation  of  the  bowels 
where  the  ova  in  the  feces  will  later  develop.  If  latrines 
were  generally  used,  uncinariasis  would  forever  disappear. 
.  .  .  [There  is]  absolute  disregard  for  sanitation  in  this 
respect  in  the  country  districts.  Practically  all  our  Utuado 
cases  stated  that  they  deposited  their  feces  in  the  open 
country,  and  had  no  latrine,  nor  even  a  hole  in  the 
ground,  for  this  purpose.  Our  special  cases  there  are  fair 
examples  of  the  average — of  sixty-one  persons,   fifty-five 


PKOPHYLAXIS.  193 

had  no  latrine.  Six  generally  used  them,  but  of  these  four 
lived  in  town.  In  Bayamon  a  much  larger  percentage  were 
more  comfortably  situated  in  life ;  three  hundred  and  forty- 
two  were  questioned  on  this  particular,  and  fifty-three 
stated  they  used  latrines;  the  others,  two  hundred  and 
eighty-nine,  never  used  one.  Thus  the  average  individual 
living  in  the  country,  barefooted  and  devoted  to  agricul- 
tural pursuits,  from  time  to  time  acquires  more  and  more 
uncinariasis  from  infections  sown  by  himself  and  his  neigh- 
bors. There  is  a  constant  inflow.  The  time  naturally  comes 
when  the  parasites  in  his  intestines  die  of  old  age,  or  some 
accident  which  cuts  their  existence." 

We  do  not  know  to  what  extent  absence  of  latrines  exists 
in  the  hookworm  area  of  the  United  States,  but  our  own 
observations  lead  us  to  agree  with  Stiles  when  he  says 
(1903): 

"As  we  go  into  the  country  and  visit  the  farms  we  not 
infrequently  find  a  condition,  in  respect  to  the  disposal  of 
fecal  discharges,  which  almost  beggars  description.  Tak- 
ing the  rural  districts  visited  during  my  recent  trips  as 
example,  it  is  not  an  exaggeration  to  say  that,  with  the  ex- 
ception of  the  planters'  premises,  not  over  half  of  the  coun- 
try houses  or  huts  of  the  sand  region  have  any  privy  at  all; 
if  there  is  one  present,  it  is  rarely  properly  cared  for.  Fur- 
thermore, it  is  the  exception  rather  than  the  rule  that  it  is 
used." 

This  and  the  resistance  of  the  larvae,  along  with  favorable 
conditions  of  temperature  and  moisture,  explain  the  danger 
of  the  disease.  The  larvae  are  scattered  by  rains,  all  traces 
of  the  feces  become  lost,  but  the  porous  moist  earth,  often 
kept  moist  and  protected  from  the  sun  by  decaying  leaves, 


194  HOOKWORM  DISEASE. 

becomes  permeated  with  the  larvae  in  the  encysted  and  in- 
fectious stage.  Mines  in  the  United  States,  for  the  most 
part,  do  not  present  favorable  temperature  conditions, 
though  there  is  room  for  further  observations  in  regard  to 
the  actual  freedom  of  our  miners  from  infection.  The  coun- 
try  is  the  place  where  practically  all  our  American  infec- 
tions take  place,  and  the  great  majority  of  infections  occur 
near  the  home — in  the  "yard,"  garden,  or  barnyard.  The 
barnyard  is  especially  dangerous  for  many  reasons.  The 
ground  conditions  are  often  ideal  for  the  development  and 
existence  of  larvae.  Chickens,  ducks,  geese,  and  hogs  scat- 
ter the  eggs  and  larvsB  in  all  directions.  Actual  feces  would 
be  avoided  by  people,  but  the  invisible  larvae  can  not  be. 

The  greater  use  of  water  closets  or  privies  in  towns  and 
the  universal  wearing  of  shoes  explain  why  hookworm  dis- 
ease is  rarer  in  cities  than  in  the  country,  and  why  the 
anemic  countryman  gradually  improves  after  he  goes  to  the 
city,  and  his  hookworms  die  off  and  are  not  kept  up  by  re- 
infection. Similar  differences  exist  in  general  between  the 
farm  and  the  cotton  mill,  so  that  the  anemic,  poorly  nour- 
ished country  girl,  after  working  for  some  months  in  the 
mill,  shows  such  a  contrast  with  her  former  self  as  one 
might  expect  under  ideal  conditions  of  country  life  if  the 
conditions  were  reversed  and  she  went  anemic  from  the  mill 
to  the  country.  Similar  improvement  gradually  follows 
when  country  children  go  to  boarding  schools. 

For  the  prevention  of  soil  infection,  the  use  of  some  kind 
of  sanitary  latrine  is  essential.  It  must  be  easily  accessible 
from  the  house  or  workplace,  so  that  neither  indolence  nor 
feebleness  will  lead  to  the  use  of  less  secure  localities.  It 
must  be  kept  clean  in  all  parts.  It  nmst  be  inaccessible  to 
animals,  and  must  be  screened  to  prevent  flies  and  other  in- 
sects from  transporting  material  from  it — a  precaution  even 
more  vnluable  for  the  prevention  of  typhoid  fever. 


PROPHYLAXIS.  195 

The  construction  may  vary  with  the  local  conditions,  es- 
pecially as  regards  water  supply,  sewerage,  and  soil.  When 
there  is  a  proper  sewerage  system,  water-closets  are  best. 
The  ova  can  not  develop  in  the  sewage,  or,  if  they  do,  will 
be  swept  away;  and  if  the  final  disposal  of  the  sewage  is 
what  it  should  be,  no  harm  can  follow. 

When  the  nature  of  the  ground  permits,  and  there  is  no 
danger  of  contaminating  wells,  deep  cesspools  are  very  ef- 
ficient. These  can  be  built  as  septic  tanks,  with  arrange- 
ments for  flushing  when  desired,  and  for  using  the  waste  as 
fertilizer,  as  devised  by  Mr.  Philbrick,  quoted  in  Parkes' 
Manual  of  Hygiene. 

Shallow  pits  or  boxes  are  objectionable  for  many  reasons, 
but  sometimes  offer  the  only  method  available.  In  such 
cases  they  should  be  treated  every  day  with  slacked  lime,  in 
order  to  disinfect  not  only  against  possible  hookworm 
larvae,  but  also  against  the  germs  of  typhoid  fever.  Leak- 
ing of  the  contents  must  be  prevented,  especially  washing 
away  from  heavy  rains,  which  could  scatter  the  larvae. 

A  better  arrangement  is  the  movable  pail  system.  In 
this,  water-tight  galvanized  iron  pails  or  buckets  are  kept 
under  the  seat  of  the  closet.  When  a  pail  is  put  in  position, 
as  after  each  cleaning,  a  thin  layer  of  sand  is  put  in  the  bot- 
tom. Enough  crude  carbolic  acid,  diluted  with  twenty 
times  its  bulk  of  water,  may  be  poured  into  the  pail.  The 
pail  must  be  easily  accessible  either  from  the  front  or  back. 
As  often  as  necessary  it  is  taken  out,  the  contents  buried  in 
a  i^it  or  trench,  covered  over  with  earth  and  quicklime,  the 
pail  cleaned  and  disinfected,  and  replaced  in  position. 

The  contents  of  the  pail  may  also  be  treated  in  a  septic 
tank,  in  which  case  no  disinfectant,  such  as  carbolic  acid, 
can  be  used.  They  should  not  be  put  where  they  can  be 
washed  away  by  rain,  nor  used  as  fertilizer,  unless  after  re- 
maining at  least  three  weeks  in  the  septic  tank.     They  must 


196 


HOOKWORM  DISEASE. 


not  be  put  on  a  manure  pile,  nor  left  where  animals  can 
scratch  over  them. 

These  arrangements,  however,  do  not  suffice  for  the  needs 
of  country  life,  as  privies  near  or  in  houses  can  not  be  util- 


Fig.  48.  A  sanitary  privy,  designed  to  prevent  the  spread  of  disease. 
If  a  privy  of  this  type  were  built  on  every  farm  and  in  every  yard  in  vil- 
lages, and  if  this  privy  were  used  by  all  persons,  typhoid  fever,  hookworm 
disease,  and  various  other  maladies  would  almost  or  entirely  disappear. 
(After  Stiles.) 


ized  at  all  times  by  all  people.  It  is  necessary,  therefore,  on 
plantations,  truck  gardens,  fruit  or  turpentine  orchards,  or 
at  charcoal  furnaces,  and  similar  places  to  have  some  sani- 
tary closet  near  the  workmen.     This  may  be  a  properly  con- 


PKOPHYLAXIS. 


197 


structed  privy,  if  the  conditions  warrant,  or  a  portable 
privy,  or  a  shelter  of  some  kind  over  a  pit  or  trench.  In 
such  cases  it  should  be  a  rule  that  dry  earth  and,  if  pos- 
sible, quicklime  should  be  used  with  a  shovel  to  cover  the 


Fig-.  49.     A  sanitary  privy  very  similar  to  that  shown  in  Fig.   48.      (After 
Stiles.) 


feces,  and  here,  too,  the  danger  of  flooding  in  rainstorms 
must  be  avoided. 

It  is  interesting  to  see  that  Moses,  who  gained  his  hy- 
gienic ideas  in  Egypt,  the  classic  home  of  hookworm  dis- 


198  HOOKWORM  DISEASE. 

ease,  ordered  for  liis  people  a  preeantion  that  might  still 
be  acted  upon  with  advantage  by  all  who  live  on  the  land  in 
hookworm  countries.  Whether  it  was  as  necessary  in  the 
Sinaitic  desert  as  in  the  Nile  valley  may  be  questioned,  but 
there  can  be  no  doubt  of  its  usefulness  in  many  populous 
cultivated  lands.  Moses  said  (Deuteronomy  xxiii,  12,  13) : 
''Thou  shalt  have  a  place  also  without  the  camp,  whither 
thou  shalt  go  forth  abroad;  and  thou  shalt  have  a  paddle 
(or  shovel,  in  Porto  Eico  the  machete  or  cutlass,  carried  by 
every  laborer,  is  recommended)  among  thy  weapons;  and  it 
shall  be  when  thou  sittest  thee  down  abroad,  thou  shalt  dig 
therewith,  and  shalt  turn  back  and  cover  that  which  cometh 
from  thee." 

In  mines,  tunnels,  canal  cuttings,  brickyards,  and  similar 
works  sanitary  closets  should  be  placed  wherever  there  is 
likely  to  be  a  need  for  them,  and  their  use  insisted  upon. 
In  the  tropical  climate  of  warm,  moist  mines  this  is  essen- 
tial on  account  of  the  unusually  favorable  conditions  for  the 
development  and  continued  existence  of  the  larvae  in  such 
places. 

It  is  instructive  to  see  what  can  be  accomplished  with  dif- 
ferent methods  of  prophylaxis  on  the  lines  described.  In 
several  mines  in  England,  Belgium,  and  Germany  efforts 
have  been  made  on  such  a  scale  as  permits  useful  con- 
clusions. 

At  the  Dolcoath  mine  of  Cornwall,  when  Boycott  and 
Haldane  {Journal  of  Hygiene^  vol.  9,  November,  1909,  pages 
264 — 270)  began  their  investigations  in  1902,  the  following 
conditions  prevailed: 

''Without  exhaustive  search  they  found  among  the  seven 
hundred  and  fifty  miners  employed  underground  fourteen 
men  with  less  than  50  percent  hemoglobin,  and  nineteen 
more  with  less  than  75  percent.     The  general  pallor  of  the 


PROPHYLAXIS.  199 

men  as  a  whole  was  very  striking,  and  complaints  of  short- 
ness of  breath  on  climbing  ladders  were  frequent.  The  dis- 
ease was  a  material  hindrance  in  carrying  out  the  work  of 
the  mine.  Examinations  of  the  men  who  complained  of  no 
symptoms  showed  that  practically  every  underground 
worker  was  infected.  The  sanitary  circumstances  of  the 
mine  were  extremely  unsatisfactory.  There  were  no  special 
arrangements  for  the  reception  of  excreta  underground,  and 
the  whole  of  the  workings  were  extensively  soiled  with 
feces. 

''Industrial  efficiency  was  obviously  confronted  here  with 
a  problem  of  some  importance.  The  steps  taken  to  escape 
the  consequences  of  ankylostomiasis  were  simple,  practical, 
and  apparently  efficacious.  ...  It  was,  in  the  great 
majority  of  cases,  very  easy  to  cure  those  actually  sick  by 
the  repeated  administration  of  appropriate  anthelmintics. 
The  effects  of  this  treatment  have  been  entirely  gauged  by 
the  clinical  results.  No  serious  attempt  has  been  made  to 
ascertain  whether  all  the  worms  had  been  killed  in  any 
particular  case  if  the  man's  general  condition  improved  so 
far  that  he  was  able  to  return  to  work.  Having  been  re- 
stored to  a  condition  of  efficiency,  the  men,  therefore,  re- 
turned to  work  in  a  place  which  was  still  infected.  They 
were,  of  course,  reinfected  again  and  again;  any  return  of 
symptoms  was  noted  at  once  and  corrected  by  .a  dose  of 
thymol.  In  this  way  actual  sickness  from  ankylostomiasis 
has  been  practically  abolished." 

At  the  same  time  steps  were  taken  to  introduce  sanitary 
reforms  into  the  underground  workings.  In  1905  a  special 
rule  was  established  by  the  secretary  of  state  for  metal- 
liferous mines  in  Devon  and  Cornwall,  as  follows: 


"The  owner,  agent,  or  manager  shall  cause  a  sufficient 


-00  HOOKWOEM  DISEASE. 

number  of  suitable  sanitary  conveniences  to  be  provided 
above  and  below  ground  in  suitable  and  convenient  places 
for  the  use  of  the  persons  employed,  and  to  be  kept  con- 
stantly in  a  clean  and  sanitary  condition,  and  no  persons 
shall  relijCve  his  bowels  below  ground  elsewhere  than  in 
these  conveniences.  No  person  shall  soil  or  render  unfit 
for  use  in  any  way  any  convenience  or  sanitary  utensil  or 
appliance  provided  for  the  use  of  the  persons  employed. ' ' 

In  1904  such  sanitary  appliances  were  actually  in  use  in 
Dolcoath  in  the  form  of  loose  buckets  or  pails,  which  could 
easily  be  brought  to  the  surface,  emptied,  and  cleaned.  In 
1908  ''the  conditions  underground  had  been  immensely  im- 
proved, the  pails  were  properly  used,  and  it  was  very  un- 
common for  the  men  to  fail  to  use  them.  .  .  .  We  could 
find  no  feces  where,  as  previous  experience  had  shown,  they 
would  be  most  probably  found.  The  general  appearance  of 
the  men  was  quite  different,  and  there  was  none  of  the 
anemia  which  had  been  so  obvious  five  years  before.  On 
carefully  going  through  two-thirds  of  the  underground 
hands  we  found  only  one  case  of  definite  anemia  in  the  per- 
son of  a  boy.  There  was  only  one  man  away  from  work 
with  symptoms  which  could  possibly  be  due  to  ankylos- 
tomiasis." Examinations  showed,  however,  that  76  per- 
cent of  the  hands  examined  were  infected,  so  that  the  im- 
proved sanitary  condition  had  put  an  end  to  material  ill- 
ness, but  had  hardly  any  effect  on  the  number  of  men  in- 
fected. ''The  sanitary  pail  system  has,  therefore,  evidently 
had  a  great  effect  in  reducing  the  inf ectivity  of  the  mine. ' ' 

Boycott  and  Haldane  compare  the  results  with  the  more 
intensive  measures  taken  in  Belgium  and  Westphalia.  In 
the  latter  every  hookworm  carrier,  as  well  as  patient,  is 
searched  out,  kept  away  from  work  on  compensation  wages, 
and  treated  until  repeated  examinations  fail  to  show  any 


PROPHYLAXIS.  201 

eggs  in  the  feces.  He  is  then  allowed  to  return  to  under- 
ground work;  but  the  workings  are  still  infective,  and  he 
"becomes  reinfected  and  the  whole  process  has  to  be  gone 
through  again  and  again." 

In  mines,  more  than  most  other  places,  disinfection  of 
the  ground  might  seem  possible,  but  the  conditions  in  large 
and  old  mines  are  such  as  to  make  this  very  difficult.  As 
has  been  shown  in  Chapter  III,  hookworm  larvae  are  diffi- 
cult to  attack.  In  the  laboratory  they  will  live  more  than 
a  year.  In  coal  water  they  live  two  or  three  weeks,  and 
have  been  found  alive  in  the  sludge  of  mines  closed  up  for 
ten  months.  They  are  sensitive  to  many  disinfectants,  but 
there  is  difficulty  in  applying  disinfectants  to  miles  of  mud 
and  water,  and  to  wet  timbers.  It  is  also  difficult  to  find 
efficient  disinfectants  that  will  not  vitiate  the  air,  or  injure 
the  boots  of  the  men  or  the  plant  in  the  mine.  Many  sub- 
stances have  been  tried;  Belger  alone  experimented  with 
41.  Ferrous  sulphate  in  1-percent  solution  is  one  of  the 
most  promising,  and  is  more  effective  than  cupric  sulphate; 
silver  nitrate,  0.05  to  0.025,  and  sodium  hydrate  or  potas- 
sium hydrate  in  1-percent  solution  kill  quickly.  Manga- 
nates  and  permanganates  have  a  decided  effect,  but  are  too 
costly  and  oxidize  too  rapidly  to  be  useful.  The  efficacy  of 
sodium  chloride  has,  however,  been  shown  by  Boycott  and 
Haldane  and  by  Calmette,  while  Manouvriez  and  Tirelli 
have  shown  that  mines  with  saline  waters  do  not  become  in- 
fected with  hookworm,  and  in  some  mines  or  tunnels  it 
might  be  found  useful. 

Boycott  and  Haldane  admit  the  superiority  of  the  Ger- 
man system  in  reducing  the  number  of  hookworm  carriers. 
This  system,  as  mentioned  above,  is  one  of  active  search 
for  ova  in  feces,  with  treatment  followed  up,  and  education 
of  the  men.  It  was  taken  up  after  sanitation  had  been  tried 
and  failed.     The  failure  depends,  in  part,  upon  the  difficul- 


202  HOOKWORM  DISEASE. 

ties  mentioned.     In  tlie  coal  mines  of  the  Ruhr  Basin  in 
Westphalia  the  proportion  of  infected  men  fell  as  follows : 

1904 13,861 

1905 4,024,  or  18  per  1,000 

1906 3,123,  or  11  per  1,000 

1907.  ?. 1,851,  or  6  per  1,000 

1908 1,171,  or  3  per  1,000 

In  the  coal  field  of  Liege,  under  the  care  of  Lambinet  and 
Malvoz,  the  proportion  fell  from  26  percent  to  4  percent  in 
two  years. 

In  Brennberg,  Goldmann  saw  a  reduction  from  85  percent 
in  1895  to  8  percent  in  1904. 

Toth  in  Schemnitz  (Hungary)  found  the  miners'  wages 
increased  60  percent  after  prophylactic  measures  were  car- 
ried out. 

Bruns,  from  Dortmund,  Germany,  reported  a  reduction  in 
the  proportion  of  infected  miners  from  35  percent  to  0.1 — 
0.2,  or  from  14,716  cases  to  1,252. 

While  all  these  improvements  have  been  very  costly,  they 
are  profitable  in  the  end,  and  they  indicate  the  task  that  a 
country  infested  with  hookworm  has  in  order  to  become 
free  from  the  tax  on  life  and  health  caused  by  that  parasite. 

In  the  open  country  chemical  disinfection  is  almost  out  of 
the  question.  Lime  in  quantities  sufficient  only  for  fer- 
tilizer would  not  be  very  efficient.  In  larger  amounts  it  is 
one  of  the  best,  as  it  combines  heat  with  disinfection.  Salt 
and  other  more  powerful  disinfectants  would  either  kill 
vegetation  or  be  dangerous  to  live  stock,  while  the  cost 
would  prohibit  their  use. 

In  hookworm  countries  the  winter  cold  does  not  kill 
larvae.  Oliver  froze  them  repeatedly,  and  kept  them  frozen 
for  six  days,  but  after  gentle  thawing  they  revived  and  gave 
rise  to  stronger  and  more  vigorous  larvae  than  those  not  so 
treated. 


PEOPHYLAXIS.  203 

Direct  sunlight  can  kill  them,  bnt  nsually  only  when  it 
dries  them  up.  They  resist  the  sun  in  northern  Europe, 
and,  although  Leichtenstern  could  not  find  them  in  the  clay 
of  brickyards,  they  find  in  some  parts  of  such  places  more 
favorable  environment. 

Drying  land  by  ditching  or  drainage  would  do  good  in 
many  places.  Plowing  is  useful  in  some  cases,  and  in 
others  the  grass  may  be  burned  over  to  kill  the  larvse. 

Sugar  fields  were  found  by  the  Porto  Eico  Commission 
to  be  rarely  the  sources  of  infection,  the  plowing  and  sun 
causing  the  death  of  the  larvae.  Tobacco  fields  also  are 
only  slightly  dangerous. 

The  larvae  are  killed  in  deep  or  moving  water,  but  can 
live  for  long  periods  in  shallow  water  along  the  edges  of 
streams — just  the  places  that  are  used  for  wading,  or  in 
some  countries  by  washerwomen  and  water-carriers — and  in 
small  puddles.  Moist  earth — especially  if  sandy,  so  as  to 
retain  moisture,  or  shaded  b}^  vegetation — offers  ideal  con- 
ditions for  the  life  of  larvae,  and  should  be  treated  accord- 
ingly in  hookworm  countries. 

3.  Prevention  of  infection  by  larvae. — On  account  of  the 
difficulty  of  preventing  the  life  and  development  of  larvae 
in  places  where  men,  women,  and  children  work,  it  is  essen- 
tial to  lessen  the  danger  of  infection  by  education.  We 
believe  that  the  problem  can  never  be  solved  without  this. 
From  the  history  of  some  other  sanitary  movements  in 
America  it  is  possible  that  the  importance  of  this  will  not  be 
recognized  by  health  officers  and  legislative  bodies.  It  is 
interesting  to  see  the  views  of  Ashford  and  King,  formed 
among  a  people  that  might  be  considered  even  less  capable 
than  our  own  of  education  in  matters  of  sanitation.  Stat- 
ing that  education  would  make  unnecessary  the  laws  re- 
garding latrines,  they  tell  how  laborers  in  Porto  Rico  an- 
noyed their  foreman  by  asking  for  latrines,  and  from  that 


204  HOOKWORM  DISEASE. 

island,  with  its  melanclioly  history  of  ignorance  and  oppres- 
sion, they  write: 

'^Law  is  not  the  instrument  best  fitted  to  compel  a  man 
to  be  cle^n  and  live  np  to  the  rules  of  hygiene.  Legisla- 
tion concerning  such  matters  would  lie  dormant  in  the 
statute  books  until  people  learn  to  appreciate  the  phi- 
losophy and  spirit  that  originate  such  measures." 

Every  one  living  in  a  hookworm  country  should  be  taught 
the  essential  facts  about  hookworms  and  their  effects.  Act- 
ual specimens,  charts  and  diagrams,  illustrations  of  pa- 
tients before  and  after  treatment,  and  clear  descriptions 
should  be  available  and  used  frequently  by  health  officers, 
school  teachers,  and  all  others  who  may  have  the  authority 
or  opportunity. 

It  is  a  reflection  on  the  common  sense  of  the  country  that 
we  have  for  years  been  spending  time  and  money  teaching 
school  children  the  evil  effects  of  alcohol,  tobacco,  pork, 
and  coffee,  while  the  children  were  in  many  cases  being 
killed  by  hookworms  before  they  were  tempted  to  drink 
whisky  or  even  to  smoke.  It  is  especially  important  here 
to  emphasize  the  fact  that  skin  infection  is  the  most  serious 
danger — the  method  of  infection  par  excellence,  as  it  has 
been  called.  Formerly  much  stress  was  laid  upon  mouth 
infection,  which,  though  rare  on  the  whole,  may  occur. 
People  should,  therefore,  be  warned  against  soiling  the 
mouth  with  muddy  hands;  eating  with  muddy  hands;  eat- 
ing muddy  vegetables  or  fruit;  drinking  muddy  water,  or 
drinking  from  muddy  receptacles;  accidental  swallowing 
of  water  while  bathing ;  earth  eating ;  carrying  home  muddy 
clothes  that  might  soil  the  hands  of  wife  or  child;  cleaning 
muddy  boots;  crawling  of  children  on  the  earth,  which  they 
put  into  their  mouths;  handling  mud-bedraggled  dresses; 


PROPHYLAXIS.  205 

eating  of  sweets  made  in  dirty  houses.  The  danger  is  es- 
pecially great  with  wet  or  moist  earth.  But  it  can  not  be 
too  often  repeated  that  in  the  great  majority  of  cases  in 
America  ground  itch  is  the  origin  of  hookworm  infection. 

It  is  fortunate  that  most  people  living  in  hookworm  dis- 
tricts know  ground  itch  by  that  name  or  one  of  its 
synonyms,  and  realize  where  and  how  they  contract  it.  If 
such  people  could  be  taught  that  ground  itch  is  the  usual 
beginning  of  hookworm  disease,  the  skin  lesion  would  as- 
sume an  importance  far  greater  than  it  now  has,  and  it 
should  be  much  easier  to  induce  methods  of  prevention.  In 
our  opinion  the  first  and  most  important  measure  to  be 
undertaken  in  the  crusade  against  hookworm  disease  in 
America  is  wide  dissemination  of  the  facts  regarding 
ground  itch,  conveying  the  information  that  when  ground 
itch  is  prevented  there  will  be  no  hookworm  disease. 

Where  ladders  are  used  in  infected  mines,  the  workmen 
must  be  warned  against  the  danger  of  infection  either 
through  the  skin  of  the  hands  and  arms,  or  the  mouth  by 
putting  infected  food  or  the  fingers  into  the  mouth.  Mine 
timbers  have  been  found  infected  as  high  as  a  meter  above 
the  ground. 

Gardeners,  and  those  who  handle  vegetables  or  fruit  that 
may  be  infected,  should  be  warned  about  hand  or  hand-to- 
mouth  infection. 

Bathing  in  common  in  tubs  should  not  be  practiced  by 
workmen,  such  as  miners,  or  country  children.  Shower 
baths  should  be  used. 

In  all  occupations — such  as  mining,  farming,  or  garden- 
ing— where  hookworm  prevails,  placards  and  other  notices 
should  be  posted,  warning  the  hands  against  the  danger  of 
skin  infection,  as  well  as  of  soil  or  water  contamination  in 
general. 

In  hookworm  localities  the  habit  of  going  barefoot  should 


206  HOOKWORM  DISEASE. 

be  avoided.  The  danger  of  a  single  experience,  as  in  wad- 
ing, should  be  clearly  understood.  Those  who  work  in  in- 
fected soil — as  in  mines,  tunnels,  or  fields — should  realize 
the  danger  of  defective  boots.  It  is  also  possible  that  boots 
soaked  f&r  hours  in  hookworm  infected  water  may  be  pene- 
trated by  larvae.  Bass  found  kid  gloves  could  be  pene- 
trated, and  Tenholt  found  that  old  boots  harbored  the 
larvae.  Various  substances  have  been  recommended  for 
the  treatment  of  boots,  such  as  grease  or  water-proofing 
material. 

The  larvae  sink  so  rapidly  in  water  that  drinking  from 
deep  pools  does  not  involve  much  danger. 


CHAPTEE  X. 


TREATMENT. 


Ground  itch  is  usually  treated  by  somebody  other  than 
the  physician,  or  not  at  all.  Of  the  home  remedies  may  be 
mentioned  bathing  the  feet  in  hot  salt  water,  mullein  tea, 
''red  oak  ooze,"  application  of  peach  tree  leaf  poultices, 
various  salves  and  ointments,  including  application  of  fresh 
turpentine  from  pine  trees,  etc.  Another  favorite  remedy, 
esjpecially  for  the  fissured  toes,  is  to  tie  around  them  a  wool 
cord  saturated  with  tallow.  Bentley  recommends  in  the 
papular  and  early  vesicular  stages  of  the  disease  the  ap- 
plication of  a  strong  solution  of  salicylic  acid  in  collodion 
or  alcohol.  This  will  cause  the  eruption  to  dry  up,  and  cut 
short  the  attack  of  the  disease  to  one  or  two  days.  If  pus 
has  formed,  the  pustules  should  be  opened  up  and  disin- 
fected with  pure  carbolic  acid,  silver  nitrate,  or  nitric  acid. 
When  great  swelling  occurs,  it  may  be  necessary  to  make  a 
few  free  skin  incisions  and  then  to  use  hot  foot  baths. 

Dalgetty  advised  the  application  of  a  strong  solution  of 
lime  and  sulphur,  or  a  strong  phenyl  (benzol)  solution;  also 
recommended  as  a  wash,  10  parts,  with  soap  5  parts,  and 
water  to  make  100  parts ;  or  the  affected  area  may  be  painted 
with  coal-tar  to  prevent  infection  with  pyogenic  bacteria. 

Stiles  cpiotes  the  following  from  an  anonymous  writer  in 
the  Journal  of  Tropical  Medicine  (1900) : 

"The  indications  are  to  get  the  case  as  soon  as  possible; 
to  carefully  cleanse  the  foot  by  soaking  it  in  warm  antisep- 
tic solution;  then  open  the  vesicles  with  sharp-pointed  scis- 
sors, snij)  the  loose  skin  away,  and  finally  wash  the  parts 

207 


208  HOOKWOKM  DISEASE. 

with  carbolic  acid  solution  (1  to  40),  and  treat  the  resulting 
ulcer  with  carbolic  acid,  phenyl  oil,  zinc  ointment,  etc.,  ac- 
cording to  circumstances.  The  soaking,  washing,  and  dress- 
ing operations  are  repeated  once  or  twice  daily,  and  heal- 
ing takes  place  in  eight  or  nine  days  in  favorable  cases. ' ' 

The  larvae  remain  in  the  skin  so  short  a  time  before  they 
get  into  the  deep  circulation,  and  entirely  out  of  reach  of 
local  remedies,  that  it  is  not  practical  to  make  applications 
that  would  even  promise  to  affect  them.  Only  symptomatic 
treatment,  therefore,  is  to  be  instituted.  The  most  dis- 
tressing symptom  is  terrible  itching,  which  often  causes  the 
patient  to  do  considerable  harm  by  scratching,  producing 
raw,  inflamed  areas,  especially  in  the  folds  between  and 
beneath  the  toes.  Deep  fissures  may  occur.  These  often 
become  infected  and  pus  is  formed.  Any  antiseptic  sooth- 
ing application  may  be  of  service  for  the  itching  and  to  pre- 
vent secondary  infection.     The  following  is  recommended: 

I^     Salicylic    acid 5  grains. 

Zinc  oxide  ointraent 2  drains. 

Vaseline  2  drams. 

Mix. 

Sig. :     Apply  locally,  twice  daily. 

It  is  especially  important  to  keeiD  the  foot  bandaged  or 
covered  to  prevent  scratching  and  rubbing.  Frequent  hot 
bathing  seems  to  hasten  the  healing  process.  This  is  prob- 
Sihlj  due  to  the  increased  circulation  induced,  hastening  re- 
moval of  the  toxic  substances  causing  the  irritation. 

The  laity  should  be  taught  that  the  common  ''toe  itch"  or 
ground  itch  is  not  a  trivial  matter,  but  that  a  physician 
should  be  consulted  at  once.  Proper  advice  and  treatment 
at  this  time  may  prevent  the  development  of  severe  disease 
later.  An  important  function  of  the  physician  called  to 
treat  a  case  of  ground  itch  is  to  urge  the  patient  to  spit  out 


TREATMENT.  209 

everything  coughed  up  for  several  days  afterwards,  ex- 
plaining that  swallowing  the  sputum  probably  means  swal- 
lowing larvae  of  dangerous  worms. 

Treatment  Before  Ova  Appear  in  the  Stools. 

Whether  treatment  to  kill  worms  in  the  intestinal  canal 
should  be  instituted  before  they  have  had  time  to  mature 
and  begin  laying  can  not  be  stated  positively.  Ashford  and 
King  say  they  know  of  many  cases  in  which  thymol  given 
previous  to  maturity  of  the  worms  failed  to  expel  them,  and 
believe  with  Leichtenstern  and  other  German  writers  that 
this  may  be  due  to  the  better  protection  given  the  small 
worms  by  mucus  and  folds  of  mucous  membrane.  If  we 
recall  the  development  of  the  worms  in  the  gut,  little  or  no 
result  could  be  expected  from  treatment  until  after  the 
infection  had  existed  for  several  days  at  least.  Though  it 
has  been  shown  experimentally  that  larvae  may  reach  the 
lungs  in  three  hours,  it  may  require  considerably  more  time 
for  them  to  reach  the  bowel,  as  is  shown  in  Chapter  III,  and 
when  they  do  reach  it  they  are  still  in  the  encysted  con- 
dition, in  which  they  are  able  to  resist  chemical  agents 
wonderfully  well.  They  were  found  by  Looss  nine,  ten, 
and  eleven  days  after  infection  in  blood  cysts  and  still  in 
the  encysted  condition.  Lambinet  states  that  the  encysted 
larvae  are  not  killed  in  a  2-percent  solution  of  corrosive  sub- 
limate after  an  exposure  of  six  hours,  nor  in  a  25-percent 
sulphuric  acid  solution  in  three-quarters  of  an  hour.  We 
do  not  know  of  any  experiments  to  determine  the  effect  of 
thymol  on  encysted  larvae,  but  from  the  foregoing  we  think 
it  is  not  likely  to  kill  them.  Bruns  concluded,  after  months 
of  laboratory  experimentation  with  every  sort  of  chemical 
disinfectant,  that  none  has  yet  been  found  to  kill  the  en- 
capsuled  larvae  so  surely  that  it  can  be  practically  used. 


210  HOOKWORM  DISEASE. 

At  least  as  early  as  about  fourteen  or  fifteen  days  after 
infection  the  worm  is  i^rovided  with  a  buccal  capsule, 
whereby  it  attaches  itself  to  and  feeds  on  the  mucous  mem- 
brane. From  this  time  on  the  parasite  is  just  as  much  ex- 
posed to  the  action  of  drugs  as  it  is  after  maturity  and  egg 
production  are  established.  Our  personal  experience  does 
not  permit  us  to  speak  with  certainty  on  this  point,  but  we 
believe  from  the  above  facts  that  treatment  should  be  begun 
fourteen  or  fifteen  days  after  the  infection,  and  that  satis- 
factory results  will  follow.  The  same  treatment  should  be 
instituted  after  an  attack  of  ground  itch  as  if  eggs  were 
jDresent  in  the  stools.  Two  or  three  courses  of  thymol  or 
beta-naj)htol  should  be  given  about  one  week  apart.  This, 
we  believe,  would  get  rid  of  most,  if  not  all,  of  the  worms 
before  they  reach  maturity  and  have  done  much  harm. 
The  stools  should  be  examined  at  the  proper  time,  and  from 
two  to  three  months  after  the  attack  of  ground  itch,  for 
eggs  of  any  worms  that  may  have  escajDcd  previous  treat- 
ment. 

Treatment  of  Hookworms  in  the  Intestine. 

It  is  important  to  understand  the  conditions  that  must  be 
met  in  the  treatment  of  hookworm  infection.  The  worms, 
three-eighths  to  three-fourths  of  an  inch  long,  lie  in  the 
small  intestine,  especially  the  jejunum.  The  head  and  some- 
times one-fiith  or  more  of  the  body  of  the  worm  is  buried 
in  the  mucosa,  and  the  whole  body  surrounded  and  pro- 
tected by  any  food  that  may  be  in  the  gut,  but  especially  by 
thick  and  tenacious  mucus,  which  is  almost  always  present. 
The  normal  amount  of  mucus  is  increased  by  the  irritation 
produced  by  the  feeding  of  many  worms.  Remedies  used 
against  the  worms  affect  or  kill  them  by  local  action,  and 
the  first  stejD  in  the  treatment  is  to  remove  this  protection 
of  chyme  and  mucus,  so  the  drug  may  come  in  contact 


TREATMENT.  211 

With  the  worms.     To  secure  an  empty  alimentary  canal  is 
not  easy.     One  who  has  had  occasion  to  examine  stools 
passed  after  the  bowels  are  supposed  to  have  been  thor- 
oughly emptied  by  a  purgative  must  be  impressed  with 
this  fact.     Sometimes  large  evacuations,  containing  recog- 
nizable food  remams,  occur.     The  upper  portions  of  the  gut 
can  be  pretty  thoroughly  freed  from  food  material  by  a 
large  dose  of  some  salts —Rochelle,  Epsom,  or  Glauber's. 
On  theoretical  grounds,  and  as  the  result  of  clinical  experi- 
ence, we  believe  that  sodium  sulphate  dissolves  and  removes 
the  intestinal  mucus  best.     Many  believe  that  calomel  or 
calomel    and    podophyllm    are    better.     The    Porto    Rico 
Anemia  Commission  tried  podophyllin  extensively  for  the 
initial  purge,  but  concluded  that  it  had  no  advantage  over 
sodium  sulphate,  and  that  its  drastic  action  may  be  harmful 
to  weak  patients.    It  is  highly  recommended  by  German 
writers  for  its  destructive  action  on  the  worms  when  given 
in  large  doses.     In  the  usual  doses,  up  to  3  centigrams  (1/2 
grain),  it  has  no  such  action.     Lambinet  recommends  jalap 
and  calomel  as  a  preliminary  purge.     Lutz  gives  1/2  gram 
(7  1/2  grains)  calomel  and  2  grams  (30  grains)  alcoholic 
extract  of  senna  leaves  one-half  day  before  beginning  the 
specific  treatment  (thymol).     Sandwith  does  not  give  any 
preliminary  purgative,   considering   it   unnecessary.     Die- 
minger  considers  the  preliminary  purge  unnecessary,  espe- 
cially when  male  fern  is  the  anthelmintic  employed.  By  hav- 
mg  a  patient  abstain  from  everything  except  the  most  easily 
digested  diet,  like  milk,  for  twenty-four  hours,  and  giving 
an  ounce  of  sodium  sulphate  at  least  four  hours  after  the 
last  feeding,  the  upper  bowel  is  usually  pretty  well  cleared 
of  food  and  mucus.     More  certain  results  can  be  had  by  giv- 
ing another  similar  purgative  twenty-four  hours  before  this 
one.     Ashford  and  King  did  not  consider  preliminary  diet- 
ing practical  with  their  Porto  Rico  cases,  or  especially  need- 


212  HOOKWOEM  DISEASE. 

ful.  Almost  all  other  authors  advise  light  diet  or  fasting 
the  day  before  specific  medication  is  employed.  It  may  not 
be  practical  in  many  instances,  we  admit,  but  we  believe  it 
is  always  advantageous  if  there  is  no  distinct  contraindica- 
tion. After  the  preliminary  preparation,  the  drug  selected 
to  kill  or  expel  the  worms  is  to  be  given  as  soon  as  the  peri- 
stalsis from  the  purgative  has  ceased,  usually  six  to  eight 
or  ten  hours.  Thymol,  beta-naphtol,  and  male  fern  are  the 
drugs  most  often  employed.  Thymol,  first  used  against 
ankylostoma  duodenale  by  Bozzolo,  is  by  far  the  most  gen- 
erally used  in  America  and  England,  and,  in  view  of  the 
almost  invariably  satisfactory  results  obtained  when  prop- 
erly administered,  it  seems  all  that  could  be  desired. 

Dose  of  Thymol. 

The  dose  of  thymol  for  internal  use,  according  to  the 
United  States  Disi^ensatory,  is  2  to  10  grains.  It  is  only 
slightly  (1:1,100)  soluble  in  water  or  the  gastric  and  intes- 
tinal juices,  and  therefore  little  absorption  occurs  when  it  is 
given  undissolved  and  on  an  empty  alimentary  canal.  Used 
as  a  vermifuge,  it  is  not  intended  to  be  absorbed,  and  is 
used  in  much  larger  doses.  Up  to  8  grams,  or  120  grains,  a 
day  have  been  taken  for  several  days  without  disturbance 
of  digestion  or  intoxication. 

Leichtenstern  recommended  two  or  three  doses  of  30 
grains  each  at  two-hour  intervals  for  several  days;  Giles, 
25  grains  in  alcoholic  solution  morning,  noon,  and  night; 
Scheube,  60  to  120  grains,  divided  into  four  doses,  adminis- 
tered one  and  one-half  hours  apart  and  followed  in  twelve 
hours  by  a  purgative;  Lutz,  30  grains,  repeated  once  or 
twice  at  two-hour  intervals;  Mosler  and  Peiper,  30  to  150 
grains  in  three  to  six  doses  during  the  day;  Sandwith,  1 
gram  (15  grains)  of  thymol  at  6  p.  m.  and  another  similar 


TREATMENT.  213 

dose  the  next  clay  at  6  a.  m.  At  8  a.  m.  about  1  ounce  (30 
grams)  of  magnesium  sulphate  is  given.  The  patient  is  on 
fever  diet  the  first  day,  but  gets  his  full  dinner  at  noon  the 
second  day.  Manson  gives  30  to  120  grains  of  thymol  in 
divided  doses  within  three  or  four  hours. 

Ashford  and  King  do  not  believe  it  necessary  or  justifi- 
able to  administer  more  than  60  grains  of  thymol  at  a  time, 
or  to  repeat  oftener  than  once  a  week.  Sandwith  says  the 
same  thing. 

Sixty  grains  to  an  adult  is  the  amount  almost  universally 
employed  in  this  country  for  a  course  of  treatment  of  hook- 
worm disease.  The  dose  for  children  should  be  in  propor- 
tion to  the  size  or  apparent  age.  Ashford  and  King's  table 
of  doses,  which  we  recommend,  is  as  follows: 

Ages.  Grains. 

Under  5  years  old  in  size 7% 

5  to  10  years  old  in  size 15 

10  to  15  years  old  in  size 30 

15  to  20  years  old  in  size 45 

20  to  60  years  old 60 

Over  60  years  old 30  to  45 

Unfavorable  conditions — such  as  great  weakness,  ex- 
treme anemia,  diarrhea,  cardiac  depression,  preg-nancy,  and 
dropsy — may  require  a  still  smaller  dose  than  that  indicated 
by  the  size. 

Mode  of  administration  of  thymol. — It  is  customary  to 
give  the  drug  in  two  or  three  "broken"  doses,  and  to  give 
them  one  or  two  hours  apart  in  order  to  prolong  the  pres- 
ence of  the  thymol  in  the  upper  bowel. 

Thymol  occurs  in  coarse  crystals.  As  it  acts  only  when 
in  contact  with  the  parasites,  it  is  more  effective  if  fimely 
powdered.  This  can  be  done  in  a  few  minutes  in  a  mortar 
with  pestle,  or  on  a  slab  with  a  spatula.  It  tends  to  pack 
together  under  pressure,  or  in  the  mucus  in  the  intestine. 
To  prevent  this,  sugar  of  milk  or  other  inert  soluble  sub- 


214  HOOKWORM  DISEASE. 

stance  should  be  mixed  with  it.  Lindeman  suggests  equal 
parts  of  thymol  and  sugar  of  milk,  and  we  find  that  this 
insures  the  proper  crumbling  or  breaking  up  of  the  con- 
tents of  the  capsule  or  wafer  when  the  latter  is  dissolved. 

We  have  often  found  in  the  stools  of  patients  who  have 
taken  thymol,  coarse  lumps,  and  a  few  times  the  entire  con- 
tents of  a  tightly  packed  capsule. 

Thymol  has  a  pungent,  acrid  taste,  and  burns  the  mouth 
and  throat.  It  should,  therefore,  be  given  in  cachets, 
wafers,  or  capsules.  A  No.  0  capsule  will  hold,  without 
packing  unduly,  5  grains  of  thymol  of  the  mixture  of  equal 
parts  of  thymol  and  milk  sugar. 

When  necessary  to  administer  it  to  children  who  can  not 
swallow  capsules  or  wafers,  it  may  be  satisfactorily  given 
suspended  in  mucilage  of  acacia  or  some  simple  syrup. 
Burning,  nausea,  and  even  vomiting  may  be  caused  by  the 
presence  of  the  pungent  thymol  in  the  stomach.  Vomiting 
can  usually  be  prevented  by  determination  on  the  part  of 
the  patient,  by  lying  on  the  right  side  to  hasten  the  passage 
of  the  medicine  through  the  pylorus,  and  by  refraining  from 
drinking  much  water.  After  the  thymol  has  presumably 
had  time  to  pass  the  part  of  the  small  bowel  where  the 
worms  are — that  is,  two  or  three  hours — it  can  not  longer  be 
of  service,  and  should  be  gotten  rid  of  by  another  brisk 
purgative  of  salts  to  prevent  its  absorption.  As  thymol  is 
soluble  in  oil,  castor  oil  should  never  be  used  for  this  pur- 
pose. The  purgative  is  not  to  move  out  the  worms,  but 
specifically  to  move  out  the  th^anol.  All  the  worms  passed 
are  dead,  and  not  much  would  be  gained  by  hastening  their 
removal  from  the  bowel  after  they  have  been  killed.  Suf- 
ficient thymol  may  be  absorbed  to  be  harmful  if  allowed  to 
remain  long  enough.  Besides  oils,  other  solvents — such  as 
alcohol  (tinctures,  whisky,  wines,  brandy,  beer),  ether, 
gl^'^cerine,  turpentine,  acetic  acid  (vinegar),  chloroform — 
and  larc'e  amounts  of  water  should  be  avoided. 


TREATMENT.  215 

Patient  to  remain  in  bed. — On  account  of  the  increased 
tendency  to  vomit  and  tlie  marlved  increase  of  toxic  symp- 
toms from  thymol  when  patients  are  up,  all  of  them  should 
be  required  to  remain  in  bed  until  the  thymol  is  moved  off. 
Either  the  bedpan  or  commode  should  be  used  in  the  room. 
We  have  seen  several  patients  get  up  and  walk  about 
against  this  instruction  without  experiencing  the  slightest 
inconvenience,  but  Sandwith  says  that  before  adopting  this 
precaution  several  instances  occurred  in  which  patients 
were  brought  back  from  the  water-closets  collapsed  or 
fainting. 

Diet  during  thymol  treatment. — In  order  to  have  the  ali- 
mentary canal  remain  clear  while  the  thymol  is  present,  ab- 
solutely no  food  or  drink  should  be  allowed,  except  water, 
from  the  time  the  preparatory  purgative  is  given  until  the 
purgative  following  the  thymol  has  acted  well.  If  the 
patient  is  very  weak  and  feels  faint,  or  if  the  burning  in  the 
stomach  is  excessive,  a  little  warm  broth  or  coffee  may  be 
allowed.  We  do  not  employ  these,  however,  except  very 
rarely.  When  one  or  two  free  movements  have  occurred 
after  the  last  purgative,  the  patient  may  begin  to  eat,  and 
his  diet  need  not  be  restricted  unless  there  is  some  special, 
indication.  He  waits  now  several  days,  usually  a  week,  be- 
fore taking  another  course.  In  the  interval  the  diet  should 
be  full  and  the  most  nutritious  compatible  with  the  patient's 
digestive  ability,  which  is  usually  good. 

Selection  of  time  for  giving  treatment. — For  apparent 
reasons,  Sunday  is  a  very  convenient  day  on  which  to  give 
the  treatment,  especially  to  working  people,  school  children, 
etc.,  as  recommended  by  Stiles.  It  is  also  convenient  to 
give  the  preparatory  purge  at  night  and  to  begin  the  thymol 
early  the  next  morning.  The  patient  then  loses  little  sleep 
the  first  night,  and  finishes  the  treatment  before  the  next 
night. 


216  HOOKWORM  DISEASE, 

We  give  our  patients  the  following  instructions,  the  closes 
being  for  an  adult: 

All  of  Saturday  have  milk  or  other  light  diet. 

Saturday,  8  or  9  p.  m.,  take  sodium  sulphate,  1  ounce. 

Sunday,  6  a.  m.,  20  grains  thymol. 

Sunday,  7  a.  m.,  20  grains  thymol. 

Sunday,  8  a.  m.,  20  grains  thymol. 

Sunday,  10  a.  m.,  1  ounce  sodium  sulphate. 

Until  4  p.  m.  do  not  eat  or  drink  anything  but  water,  and 
but  little  of  that.     Eemain  in  bed. 

After  4  p.  m.  rise  and  eat  what  you  want  and  do  what- 
ever you  feel  like  doing. 

Thymol  may  affect  the  patient  unfavorably  in  three  gen- 
eral ways — by  intoxication,  by  irritating  the  kidneys,  and 
by  irritating  the  stomach  and  intestine. 

Thymol  intoxication  symptoms. — The  effects  of  absorp- 
tion of  a  large  amount  of  thymol  are  headache,  weakness, 
dizziness,  tinnitus,  nausea;  rapid,  weak  pulse,  and  some- 
times sweating  of  the  face  or  body;  cyanosis  of  lips  and 
fingers.  The  temperature  in  one  instance  fell  5  to  10  de- 
grees F.  Frequently  none  of  these  symptoms  are  felt  until 
the  patient  gets  out  of  bed.  The  intensity  of  the  symptoms 
must,  of  course,  depend  on  the  amount  of  thymol  absorbed 
and  the  individual  susceptibility.  Thymol  is  soluble  in  al- 
cohol and  volatile  oils,  and  these  should  be  rigidly  inter- 
dicted. In  fact,  the  patient  should  be  instructed  absolutely 
not  to  swallow  anything  except  water,  and  to  drink  only  a 
small  quantity  of  that.  Many  cases  of  intoxication  are  due 
to  drinking  too  much  water.  The  importance  of  this  is 
often  overlooked.  Thymol  is  sufficiently  soluble  in  water, 
about  1/2  grain  to  the  ounce,  for  the  patient  to  absorb  a 
toxic  dose  if  he  drinks  large  quanties  of  water.  The  infre- 
quent occurrence  of  toxic  symptoms  from  thymol  given  in 
the   doses   mentioned   is   suggested  by  the   fact  that   the 


TREATMENT.  217 

authors  have  treated  several  hundred  cases  without  ever 
seeing  more  than  a  little  dizziness  and  weakness  as  a  result. 
We  have  heard,  however,  of  alarming  s^Tnptoms,  but  not  of 
any  fatal  cases.  In  one  instance  a  family  of  four  children 
was  poisoned  by  the  usual  doses  of  thymol  calculated  ac- 
cording to  their  ages.  The  symptoms  were  weakness,  diz- 
ziness, fainting,  and  unconsciousness.  One  child  fainted 
when  returning  from  the  water-closet  and  the  other  three 
got  out  of  bed  and  came  to  her  assistance,  but  each  one 
fainted,  and  it  was  necessary  to  carry  all  four  of  them  back 
to  bed.  All  had  been  given  castor  oil  two  hours  after  the 
last  dose  of  thymol,  and  the  one  who  fainted  first  had  eaten 
a  slice  of  bread  and  butter.  In  six  hours  afterward  they 
were  all  in  the  yard  playing.  Two  days  after  the  poison- 
ing the  urine  was  examined  and  found  free  from  albumin. 
We  have  several  times  noted  that  patients  who  complain  of 
dizziness  and  other  symptoms  of  intoxication  seem  to  re- 
cover and  feel  well  remarkably  early  after  the  purgative 
acts  well  and  food  is  taken.  They  are  usually  able  to  get 
up  at  once,  and,  though  unpleasant  recollections  of  the  re- 
cent experience  remain,  the  symptoms  have  entirely  dis- 
appeared. 

Eecently  a  university  student  treated  by  our  colleague. 
Dr.  Gage,  took  60  grains  of  thymol  and  two  hours  afterward 
a  drink  of  whisky  to  "wash  down"  the  dose  of  salts.  There 
followed  several  free  movements  during  each  of  this  and 
the  next  three  days.  The  patient  was  up  and  felt  fairly 
well,  but  a  little  weak.  On  the  fifth  day  he  had  a  mild  col- 
lapse, with  dizziness  and  severe  headache  lasting  a  few 
hours.  Eructations  tasting  strongly  of  thymol  occurred 
frequently.  During  the  next  three  days  several  dysenteric 
stools  were  passed.  It  was  eight  or  ten  days  before  the 
patient  felt  entirely  well  in  his  head  and  in  his  bowels. 
The  eructations  of  thymol  and  mild  collapse  five  days  after 


218  HOOKWORM  DISEASE. 

it  had  been  taken  indicate  that  it  had  not  been  eliminated 
in  this  instance,  in  spite  of  several  free  bowel  movements. 

Pregnancy  contraindicates  the  administration  of  thymol, 
except  under  the  greatest  care,  for  fear  of  producing  abor- 
tion, which  it  occasionally  does.  Nephritis  and  consider- 
able edema  are  also  contraindications. 

Ashford  and  King  note  that  in  very  edematous  patients 
the  effect  of  large  doses  of  thymol  is  particularly  harmful. 
By  the  next  day  the  edema  is  much  increased  and  often  in- 
volves the  brain.  Albumin  and  casts  are  increased  in 
nephritic  cases  when  large  doses  of  thymol  are  admin- 
istered. 

We  saw,  however,  a  very  severe  case  of  hookworm  dis- 
ease in  a  child  of  16  who  had  60  percent  of  moist  albumin 
by  the  Purdy  acetic  acid  and  ferrocyanide  test  when  she 
was  given  30  grains  of  thymol.  No  untoward  results  were 
noted,  and  2,760  imcinariae  were  expelled.  Three  days  after 
the  thymol  was  given  the  urine  showed  only  18  percent  of 
albumin  by  the  same  test.  The  effect  of  thymol  on  the 
normal  gastro-intestinal  canal  is  occasionally  burning  epi- 
gastric pain,  nausea,  and  vomiting,  and  more  or  less  diar- 
rhea. If  diarrhea  or  dysentery  already  exist,  they  are 
promptly  aggravated  by  large  doses.  In  several  instances 
we  have  seen  loose  bowels,  lasting  two  or  three  days,  follow 
administration  of  thymol.  One  case  had  six  to  twelve 
movements  a  day  for  six  days.  The  rectum  and  anus  are 
irritated  by  tlnTiiol  passing  out  with  the  feces,  and,  if 
hemorrhoids  or  fissures  are  present,  this  symptom  is  much 
increased. 

The  degree  of  debility  must  be  taken  into  account  when 
cousidering  the  size  of  the  dose  for  a  given  case.  A  very 
weak  subject  should  receive  not  more  than  15  to  30  grains 
the  first  dose,  Avhich  will  usually  relieve  him  so  that  he  can 
resist  a  full  dose  next  time.     Some  English  writers  do  not 


TREATMENT.  219 

believe  tlie  small  doses  accomplish  much,  but  actually  large 
numbers  of  worms  are  sometimes  expelled  as  a  result  of 
them. 

The  Porto  Rico  Anemia  Commission  treated  112,580  cases 
of  hookworm  disease  during  the  years  1904  to  1907  in- 
clusive, all,  except  relatively  few,  with  thymol,  and  after 
this  extensive  experience  advise  placing  the  thymol  in  the 
hands  of  patients  to  carry  home  and  take  according  to 
directions.  Boycott  and  Haldane,  as  well  as  many  other 
recent  writers,  have  had  no  dangerous  symptoms  such  as 
were  described  by  some  early  observers,  probably  from  giv- 
ing oil  or  alcohol  after  the  thymol. 

Treatment  of  toxic  S5miptoms  produced  by  thymol. — Car- 
diac stimulants,  such  as  a  hypodermic  of  a  small  dose  of 
morphine  (1/6  grain)  and  atrophine  (1/120  grain),  or 
strychnine  (1/30  grain),  or  digitalin  (1/100  grain),  are  of 
service  in  combating  toxic  symptoms.  Hot  coffee  has  been 
recommended  for  the  weakness  sometimes  present.  It  is 
customary  with  some  to  give  strychnine  and  digitalis  for  a 
day  or  two  preceding  the  day  thymol  is  given.  This  seems 
unnecessary,  except  with  extremely  weak  patients.  Alco- 
holic stimulants  or  tinctures  by  mouth  must  be  rigidly 
avoided  on  account  of  the  danger  of  dissolving  and  render- 
ing absorbable  more  thymol.  One  of  the  most  important 
things  is  to  keep  the  patient  lying  down.  If  fainting  occurs, 
the  head  should  be  lowered,  as  in  fainting  from  other  causes. 
The  irritation  to  the  kidneys  by  thymol,  if  properly  given, 
is  negligible  unless  much  is  absorbed.  Even  then  the  irri- 
tation rapidly  subsides  without  treatment  after  the  drug  is 
stopped.  The  diarrhea  sometimes  occurring  after  the 
thymol  administration  soon  passes  off  without  requiring 
treatment.  If  treatment  is  demanded,  it  should  be  along- 
general  lines. 


220  HOOKWORM  DISEASE. 

Results  to  be  expected  from  thymol  in  expelling  worms. — 

The  first  course  of  thymol  properly  given  usually  gets  rid 
of  80  to  90  percent  of  all  the  worms  present.  So  good  a  re- 
sult is  obtained  only  when  proper  preparation,  etc.,  are 
observed.  One  of  the  secrets  of  successfully  treating  intes- 
tinal parasites  of  all  descriptions  is  to  secure  an  empty  ali- 
mentary canal  before  the  specific  drug  is  given.  This  is  so 
important  that  we  do  not  doubt  that  it  is  often  much  better 
to  give  a  purgative  on  Friday  night  as  well  as  on  Saturday 
night.  There  are,  no  doubt,  other  factors  that  prevent 
marked  success  in  some  cases,  such,  for  instance,  as  the 
rapid  carrying  down  of  the  thymol  by  peristalsis  to  below 
the  location  of  the  worms.  For  this  reason  it  is  desirable 
not  to  begin  the  thymol  until  peristalsis  from  the  purgative 
has  ceased.  It  should,  however,  be  given  soon  afterward 
and  before  the  worms  are  again  protected  by  the  mucus, 
which  soon  forms.  Cases  are  often  met  with  in  which  no 
eggs  are  found  after  one  course  of  thymol,  a  fact  known  to 
German  miners  seeking  work.  In  many  more  a  few  remain 
until  three  or  four  courses  are  given,  and  in  a  few  cases  six 
to  eight  or  ten  courses  are  required  to  get  rid  of  all  of  them. 
It  can  be  said,  however,  that,  if  persisted  in,  thymol  will 
always  succeed.  It  is  even  a  better  specific  for  hookworm 
disease  than  quinine  is  for  malaria. 

In  a  very  extensive  experience  reported  by  Ashford  and 
King,  97.8  percent  of  those  who  expelled  all  their  uncinarias 
received  thymol  five  times  or  less.  Of  these  41.8  percent  ex- 
pelled all  after  one  treatment,  32.1  percent  after  two  treat- 
ments, 14.2  percent  after  three  treatments,  6.8  percent  after 
four  treatments,  and  2.8  percent  after  five  treatments.  Of 
4,474  cases  which  received  thymol,  81.1  percent  expelled  all 
uncinariae,  but,  subtracting  507  who  never  returned  or 
ceased  to  return  after  two  or  more  treatments,  this  percent- 
age rises  to  91.5  percent.     Sandwith  cured  95  percent  of  185 


TKEATMENT. 


221 


cases  of  ankylostomiasis  with  five  or  less  doses  of  thymol. 
The  cures  in  the  185  cases  were  effected  in  the  following 
manner : 

Number  After  number  of 

cured.  treatments  with  thymol. 

42 1 

58 2 

43 3 

25 4 

9 5 

4 6 

2 7 

2 8 

It  would  seem,  therefore,  that  the  old  world  hookworm  is 
about  as  easy  to  expel  as  the  American  variety. 

In  our  own  experience  about  one-half  of  all  cases  have 
been  cured  of  all  their  worms  with  three  courses  of  thymol; 
several  have  required  five,  six,  and  seven  treatments,  and 
one  required  ten  full  treatments.  In  the  case  already  men- 
tioned, 2,760  worms  were  expelled  after  one  treatment,  but 
the  highest  number  counted  in  any  other  case  was  1,054. 

We  have  often  been  impressed  with  the  fact  that  many, 
in  this  country  at  least,  do  not  fully  appreciate  that  the 
treatment  must  generally  be  repeated  several  times  before 
all  worms  are  expelled.  The  complaint  is  made  that,  though 
some  worms  are  expelled  after  a  course  of  thymol,  the 
patient  is  not  cured.  We  would  reply  that  few  other  dis- 
eases are  cured  by  a  single  day  of  treatment. 

Repetition  of  treatment. — On  account  of  the  irritation  to 
the  alimentary  canal  and  kidneys  produced  by  thymol,  most 
authors  agree  that  it  should  not  be  repeated  oftener  than 
once  a  week,  unless  there  is  some  special  indication  for  it. 
We  have,  however,  several  times  given  a  course  of  thymol 
every  third  or  fourth  day  for  several  times,  and  have  not 
seen  any  harm  result  therefrom.  We  believe  it  is  a  good 
plan  to  give  three  treatments  one  week  apart,  and,  after 


222  HOOKWORM  DISEASE. 

waiting  about  a  week,  to  examine  the  feces  for  ova.  Usu- 
ally in  mild  or  medium  cases  none  will  be  found.  If  any  are 
found,  treatment  must  be  repeated.  It  must  be  remem- 
bered that  sometimes  ovulation  is  suspended  temporarily 
after  thymol  has  been  administered,  and,  if  symptoms  per- 
sist, the  feces  should  again  be  examined  in  three  or  four 
weeks  after  the  last  treatment.  The  result  of  the  treatment, 
can  thus  be  best  determined. 

Other  Methods  of  Treatment. 

Beta-naphtol. — Beta-naphtol,  as  advocated  by  Bentley,  is 
given  with  the  same  precautions,  preparation  of  patient, 
and  the  same  after-treatment  as  with  thymol.  Colbert  had 
one  patient  who  expelled  4,016  worms  from  one  dose  of  beta- 
naphtol.  Beta-naphtol,  however,  seems  to  act  well  only 
when  the  preliminary  purgation  and  fasting  have  been  car- 
ried out  thoroughly.  If  food  is  taken,  very  poor  results  are 
often  obtained.  Ashford  and  King  concluded  that  thymol 
was  superior  to  beta-naphtol  where  the  patient  was  not 
under  control,  and  state  that  they  were  obliged  to  abandon 
the  use  of  the  latter  for  walking  patients  on  this  account. 
They  speak  of  several  instances  in  which,  after  repeated 
doses  of  beta-naphtol  were  given,  eggs  were  persistently 
present  in  the  feces,  which  cleared  up  after  a  single  dose  of 
thymol.  Bentley  states  that  he  abandoned  thymol  two 
years  before  to  use  beta-naphtol,  and  has  used  it  in  several 
thousand  cases  with  excellent  results.  The  dose  is  one-half 
that  of  thymol — viz.,  30  grains  for  an  adult.  It  frequently 
is  successful  in  expelling  worms,  but  in  many  patients  who 
took  their  medicine  at  home  the  Porto  Rico  Anemia  Com- 
mission found  the  number  of  worms  expelled  far  less  than 
when  thjmiol  was  administered.  On  the  other  hand,  a  com- 
parison of  forty  hospital  cases  treated  with  thymol  and 
thirty  treated  with  beta-naphtol,  in  which  the  number  of 


TREATMENT.  223 

worms  expelled  was  carefully  determined,  shows  the  results 
from  each  drug  to  be  about  equal.  The  finding  of  the  com- 
mission shows  the  following  percentages  of  all  worms  in  the 
intestinal  canal  of  the  patient  that  were  expelled : 

Percentage  of 
total  number  of 
worms  expelled. 

After  1  dose     of  thymol 76.85 

After  1  dose    of  beta-naphtol 72.24 

After  2  doses  of  thymol 90.17 

After  2  doses  of  beta-naphtol 88.12 

,    After  3  doses  of  thymol 95.28 

After  3  doses  of  beta-naphtol 93.67 

After  4  doses  of  thymol 96.57 

After  4  doses  of  beta-naphtol 96.47 

Beta-naphtol  is  more  irritating  to  the  kidneys,  and  some- 
times sets  up  considerable  nephritis.  There  is  already  al- 
buminuria in  many  cases  of  uncinariasis,  and  it  seems  un- 
wise to  select  a  drug  irritating  to  the  kidneys.  Unpleasant 
dizziness  often  results  from  its  use.  It  is,  however,  less 
depressing  than  thymol.  Its  cost  is  only  about  one-tenth 
that  of  thymol. 

Oleoresin  of  male  fern.— Male  fern  has  been  used  for  a 
very  long  time  as  an  anthelmintic  in  treating  tapeworms, 
and  has  recently  been  much  used  on  the  continent  of  Europe 
in  ankylostomiasis.  Of  21,612  cases  treated  in  Westphalia 
by  Bruns  it  failed  to  expel  all  the  parasites  in  only  1.5  per- 
cent, and  in  only  15  to  30  percent  of  cases  was  it  necessary  to 
give  a  second  dose.  He  records,  however,  four  cases  of 
blindness  resulting  from  its  use.  Tenholt  cured  95.8  per- 
cent of  his  cases  with  three  doses.  Lambinet  gives  a  purge 
of  calomel  and  jalap  powder  the  night  before,  and  on  the  fol- 
lowing morning  "Duhourgan's  teniafuge  francais,"  which 
is  ext.  filic.  mas.  4  grams,  chloroform  3  grams,  ol.  ricini  40 
grams.  This  is  given  in  two  doses,  with  an  hour's  interval, 
and  repeated  the  next  day.     Toth  recommends  45  to   75 


224  HOOKWORM  DISEASE. 

grains  filix  mass,  with  a  glass  of  liqueur,  every  day  for  four 
or  five  days.  Dieminger  noted  icterus,  gastritis,  and  gas- 
tro-enteritis  in  some  cases,  as  has  also  been  noted  by  Toth 
and  others. 

Leichtenstern  says  that  150  grains  should  not  be  ex- 
ceeded.^ Ashford  and  King  tried  ethereal  extract  of  male 
fern  in  Porto  Eico,  and  say  that  in  some  cases  in  which  the 
parasites  were  resistant  to  thymol  this  gave  good  results 
and  in  others  it  did  not.  They  suggest  that  the  deleterious 
effect  of  the  hot  climate  of  Porto  Rico  on  the  drug  may  have 
been  responsible  for  the  variable  results  obtained.  In  their 
1905  preliminary  report  they  say:  ''The  highest  number  of 
uncinarise  expelled  by  either  of  these  preparations  (solid 
extract  and  fluid  extract)  was  eight,  while  a  subsequent 
administration  of  only  three-fourths  of  the  usual  dose  of 
thymol  brought  away  3,686,  and  this  in  the  very  same 
case."  It  seemed  to  cause  more  dizziness  and  nausea,  and 
patients  complained  that  they  felt  sicker  and  weaker  after 
it  than  after  thymol.  The  drug  is  very  variable  in  its 
potency,  and,  though  we  have  not  experimented  with  it  in 
this  disease,  we  believe  that  its  use  will  be  limited,  by  its 
much  greater  cost  and  other  objections  mentioned,  to  cases 
that  have  failed  to  be  cured  by  thymol  or  beta-naphtol. 
The  same  preliminary  treatment  is  to  be  given,  and  75  to 
150  grains  of  oleoresin  of  male  fern  administered  in  two 
divided  doses  one  hour  apart. 

Eucalyptus. — Phillips  recommends  eucalyptus  oil  com- 
bined with  chloroform  and  castor  oil.  The  following  is  di- 
vided into  two  doses  and  given  one-half  hour  apart: 

01.   eucalypti 2.5  grams. 

Chloroformi   3.5  grams. 

01.   ricini 41.     grams. 

This  is  not  easily  administered,  and  is  very  nauseating, 
but  has  the  advantage  of  causing  live  worms  to  be  expelled. 


TREATMENT.  225 

Podophyllin. — Podopliyllin  is  recommended  by  Neumann, 
who  thinks  a  certain  amount  of  inflammation  of  the  intes- 
tine favorable,  if  not  indispensable,  for  expulsion  of  the 
worms.  It  is  not  very  toxic,  but  irritating  to  the  mucous 
membrane.  He  gives  two  pills  a  day  of  0.045  milligrams 
of  the  active  principle  for  four  days,  and,  if  ova  still  per- 
sist, he  gives  male  fern. 

Other  Drugs. — The  following  other  drugs  have  been  men- 
tioned by  various  writers: 

1.  Juice  of  ficus  doliaria,  3  to  6  teaspoonful  doses; 
much  used  in  Brazil. 

2.  Powdered  areca  nut. 

3.  Jorrissen's  preparation  (a  costly  one) — terpine  1/2 
gram,  levigated  sulphur  2  grams,  condurango  powder  1 
gram. 

4.  Infusion  of  bark  of  acacia  anthelmintica. 

5.  Oil  of  peppermint. 

6.  Kerosene  oil. 

7.  Guaical  carbonate. 

8.  Thymotal. 

General  Treatment. 

Anemia. — The  same  general  principles  of  the  treatment 
of  anemia  from  other  causes  apply  also  to  the  treatment  of 
this,  the  most  constant  and  the  most  prominent  symptom 
of  hookworm  disease.  The  most  important  measure  is,  of 
course,  to  remove  the  cause,  but,  inasmuch  as  this  often  re- 
quires three  to  six  weeks,  and  the  patient  must  rebuild  his 
blood  during  and  after  this  time  before  he  is  back  to  normal 
health,  the  question  arises  as  to  what  treatment  may  be 
made  use  of  to  hasten  blood  formation.  Pure  air,  sunlight, 
and  nutrition  are  the  most  important  factors.  The  class  of 
people  affected,  except  miners  and  tunnel  workers,  are 
blessed  with  air  and  sunlight.     In  most  cases  the  removal 


226  HOOKWOKM  DISEASE. 

of  a  large  portion  of  the  worms  is  i3romptly  followed  by  in- 
creased appetite,  and  when  the  digestion  and  assimilation 
are  good,  as  they  usually  soon  become,  nutrition  is  increased 
far  above  that  required  for  a  normal  individual.  We  do  not 
believe  special  dieting  necessary,  or  even  api3reciably  bene- 
ficial, for  mild  or  medium  cases,  but  that  liberal  general  diet 
should  be  allowed.  Very  severe  cases,  with  weak  digestion 
and  assimilation,  are  no  doubt  benefited  by  a  wise  selection 
of  easily  digested,  nutritious  diet  suited  to  the  individual 
case.  An  abundance  of  good  general  diet  is  what  is  re- 
quired for  most  rapid  recovery.  If  we  recall  the  fact  that 
not  only  is  the  blood  below  normal  in  hookworm  disease,  but 
many  of  the  other  body  tissues  as  well — bone,  muscle,  nerve, 
hair,  skin,  etc. — the  importance  of  a  general  mixed  nutri- 
tious diet  becomes  apparent. 

The  anemia  in  most  cases  is  of  the  secondary  type,  with 
low  hemogiobm  and  low  color  index,  which  is  generally 
benefited  by  administration  of  iron,  one  of  the  essential  ele- 
ments in  hemoglobin.  Very  mild  and  mild  cases  probably 
are  not  appreciably  affected  by  iron,  but  all  moderate  and 
severe  cases  should  take  some  form  of  this  drug  in  the  inter- 
val between  thymol  treatments.  AVe  admit,  with  all  other 
writers  on  this  subject,  that  the  importance  of  iron  in  the 
treatment  of  hookworm  disease,  compared  with  specific 
treatment  against  the  worm,  is  very  small.  We  also  believe 
that  recovery  from  almost  any  grade  of  hookworm  anemia 
will  follow  expulsion  of  the  worms  as  certainly  without  as 
with  iron  treatment,  but  that  it  will  generally  be  more  or 
less  hastened  thereby.  In  fact,  the  anemia  is  benefited  de- 
cidedly by  iron,  either  alone  or  combined  with  bitter  tonics, 
without  any  specific  treatment  being  directed  against  the 
worms.  Many  patients  with  chronic  severe  uncinariasis 
give  the  history  of  taking  iron  tonics  or  reduced  iron  year 
after  year.     They  get  run  down,  weak,  and  more  anemic  every 


TREATMENT.  227 

spring,  but  get  sufficient  relief  from  iron  to  carry  them 
through  the  summer,  never,  however,  getting  entirely  well. 
Lookiug  back  over  an  experience  of  many  years  spent  in  a 
section  of  country  heavily  infected  with  this  disease,  we 
recall  several  families  that  we  now  know  were  severely  in- 
fected, and  that  bought  year  after  year  their  supply  of  re- 
duced iron,  which  was  kexDt  in  the  country  stores.  We  re- 
call that  another  method  of  administering  iron  was  to  place 
some  nails,  or  iron  scraps  and  scales  from  the  blacksmith 
shop,  in  a  bottle  with  vinegar,  with  or  without  some  bark 
and  herbs  added,  for  a  bitter  tonic.  Some  old  man  or  old 
woman  of  the  neighborhood,  frequently  a  grandmother  of 
several  families,  was  supposed  to  know  best  how  to  make 
these  "spring  tonics,"  which  generally  contained  iron. 
Since  the  country  has  settled  up,  and  railroads  and  towns, 
and  drugstores  and  more  doctors  and  patent  medicines  have 
come  in,  there  is  far  less  of  this  self-medication,  but  the 
point  we  desire  to  make  is  that  iron  is  sufficiently  beneficial 
in  hookworm  disease,  without  the  worms  being  treated,  to 
direct  the  patients  themselves  to  continue  to  use  it. 

The  history  of  Dr.  T.  B.  Ford,  who  practiced  for  many 
years  in  a  heavily  infected  section  of  Mississippi,  is  inter- 
esting in  this  connection.  Dr.  Ford  (now  retired)  was  a 
close  observer,  and  much  cleverer  than  the  average  country 
practitioner.  Long  before  hookworm  disease  was  diag- 
nosed in  this  country  he  had  learned  that  there  was  a  spe- 
cific anemic  disease,  the  cause  of  which  he  did  not  know.  He 
could  not  cure  it,  but  it  was  always  benefited  by  iron  and 
quinine  pills,  which  he  made  up  himself.  They  were  made 
of  reduced  iron,  quinine  sulphate,  and  extract  of  gentian. 
He  frequently  varied  the  proportions  to  meet,  as  he  thought, 
special  indications,  but,  as  we  remember  it,  each  pill  con- 
tained from  one-half  to  one  grain  each  of  the  iron  and 
quinine.     The  disease  was  so  prevalent  in  that  country,  and 


228  HOOKWOEM  DISEASE. 

the  benefit  derived  from  "Dr.  Ford's  iron  and  quinine 
pills"  so  apparent,  that  they  were  known  by  the  laity  for 
thirty  or  forty  miles  around  to  be  a  specific  remedy  for  this 
unknown  disease. 

There  is  evidence  that  iron  hastens  blood  reconstruction 
and  none  that  it  interferes  with  it,  or  is  otherwise  harmful; 
therefore  some  form  of  iron  should  be  given  in  moderate  or 
severe  anemia  cases.  Stiles  believes  that  it  should  not  be 
given  between  the  first  and  second  treatments  with  thymol, 
in  order  to  impress  on  the  patient  the  fact  that  the  thymol 
is  actually  the  source  of  benefit  and  must  be  continued.  The 
patient  usually  improves  so  much  during  the  first  week  that 
any  skepticism  he  may  have  had  as  to  the  correctness  of 
the  diagnosis  is  dispelled.  The  same  principles  would  gov- 
ern the  selection  of  the  form  of  iron  here  as  in  the  treatment 
of  any  other  secondary  anemia.  Blaud's  pills,  five  grains, 
t.  i.  d.,  and  iron  (reduced),  quinine,  and  gentian,  1/2  to  1 
grain  of  each,  t.  i.  d.,  are  recommended.  Sandwith  gives 
7  1/2  grains  of  sulphate  of  iron  t.  i.  d.,  the  best  results  being 
obtained  when  this  is  preceded  by  extract  of  bone  marrow 
for  about  a  week. 

A  few  cases  of  long  standing  and  usually  severe  hook- 
worm disease  develop  the  pernicious  type  of  anemia,  with 
high  color  index,  and  are  not  benefited  by  iron,  as  would  be 
expected.  Many  of  them  recover  very  slowly,  or  never  re- 
turn to  a  perfectly  normal  blood  condition.  They  are  bene- 
fited by  arsenic  in  the  form  of  Fowler's  solution,  and  should 
take  five  to  ten  drops  t.  i.  d.  over  long  periods  of  time,  with 
occasional  short  intervals  of  rest.  Such  a  case,  age  24,  first 
seen  four  years  ago,  gave  a  history  indicating  hookworm 
disease  since  early  childhood,  and  the  feces  showed  what 
we  considered  a  mild  infection,  which  was  confirmed  by  the 
expulsion  of  twenty-four  worms  following  60  grains  of 
thymol,  after  which  no  eggs  could  be  found  on  several  ex- 


CHART 

1. 

Eosino- 

Hemo- 

Color 

philes, 

D 

ate. 

globin. 

Red  cells. 

index. 

percent. 

May 

4,1906. 

..48 

2,010,000 

1.2 

18 

May 

11, 190G. 

..45 

2,100,000 

1.1 

16 

May 

25,1906. 

..52 

2,250,000 

1.2 

11 

July 

6,1906. 

..43 

1,910,000 

1.1 

Sept. 

14,1906. 

..50 

3,214,000 

0.8 

8 

Feb. 

6,  1907 . 

..62 

4,116,000 

0.8 

4 

Nov. 

12,1907. 

..71 

4,860,000 

0.7 

2 

Jan. 

21,1908. 

..84 

4,920,000 

0.9 

4 

July 

11,1909. 

..81 

4,741,000 

0.9 

1 

TREATMENT.  229 

aminations  extending  over  six  weeks'  time.  The  blood  con- 
dition at  different  times  and  the  treatment  is  shown  by  tlie 
following  table: 


Treatment. 
Thymol  and  Blaud's  pills. 
Thymol  and  Blaud's  pills. 
Thymol  and  Blaud's  pills. 
Fowler's  solution. 
Fowler's  solution. 
Fowler's  solution. 
Treatment  discontinued. 
Treatment  discontinued. 
Treatment  discontinued. 

There  were  present  a  few  normoblasts,  poikilocytosis,  and 
anisocytosis  all  the  time  until  the  arsenic  treatment  was 
begun.  It  will  be  seen  from  the  chart  that  there  was  no 
gain  until  the  arsenic  was  begun,  regardless  of  the  fact  that 
all  the  worms  had  been  expelled  and  the  patient  took 
Blaud's  pills  all  the  time.  That  the  patient  did  not  have 
pernicious  anemia  is  indicated  by  the  nearly  normal  blood 
for  over  two  years.  We  have  seen  several  patients  showing 
this  type  of  anemia,  and  always  making  slow  or  no  improve- 
ment after  curing  them  of  their  worms.  In  fact,  we  know 
four  cases  still  anemic,  notwithstanding  that  two  of  them 
were  cured  of  their  worms  more  than  two  years  ago.  Such 
cases  demonstrate  that  hookworm  disease  may  in  some  way 
damage  the  blood-making  organs  to  an  extent  and  in  a  way 
that  makes  recovery  impossible.  Fortunately,  such  cases 
are  relatively  very  few  in  this  country.  The  only  way  we 
know  to  recognize  them  certainly  is  by  proper  blood  exami- 
nation. 

Improvement  After  Treatment. 

There  are  indeed  few  diseases  in  which  treatment  is  fol- 
lowed so  promptly  and  so  certainly  by  unmistakable  im- 


230  HOOK  WOE  ^I  DISEASE. 

provement  and  recovery  as  is  proper  anthelmintic  treat- 
ment in  hookworm  disease.  This  is  one  of  the  few  specifics 
in  medicine.  The  improvement  in  severe  cases  is  marvelous. 
A  child  with  15  or  20  percent  hemoglobin,  pale,  "  tallow- 
faced,  V  one-fourth,  one-third,  or  even  one-half  under 
weight,  undeveloped,  dyspneic,  and  languid,  can  be  seen  to 
gain  weight,  height,  and  color  almost  daily,  and  often  with- 
in two  or  three  months  be  converted  by  a  few  doses  of 
thymol  into  a  red-faced,  hardy,  healthy-looking  child.  He 
often  grows  more  in  one  year  after  treatment  than  he  had 
in  the  previous  five,  or  even  ten,  years.  Xature  seems  to 
try  to  make  up  for  lost  time,  and,  though  the  child  may 
never  attain  the  size  he  would  have  attained  if  he  had  not 
been  infected,  the  gain  is  great  and  rapid.  Among  the  im- 
portant factors  determining  the  length  of  time  necessary  for 
a  patient  to  regain  his  health  and  completely  recover,  and 
whether  complete  recovery  can  result,  are:  the  severity  of 
the  disease,  the  age  of  the  patient,  and  individual  recupera- 
tive powers.  It  must  be  remembered  that  hookworm  disease 
may  be  produced  by  any  number  of  worms  from  one  up  to 
the  lethal  dose,  sometimes  as  high  as  four  or  five  thousand. 
This  very  variable  number  of  worms,  as  well  as  other  fac- 
tors, necessarily  gives  rise  to  differences  of  intensity.  One 
patient  may  be  so  badly  affected  as  to  require  months  to  re- 
cover or  to  preclude  complete  recovery,  whereas  another 
may  return  to  full  health  in  a  few  days.  TVe  have  long 
been  impressed  with  the  influence  of  age  on  the  recovery 
from  hookworm  disease,  young  or  growing  patients  always 
gaining  much  more  rapidly  than  adults.  "We  shall  say  more 
about  this  below  under  ''height  and  weight."  Individual 
recuperative  powers  are  here  of  much  importance,  as  in 
many  other  diseases.  Two  individuals  cured  of  their  worms 
and  having  equal  amounts  of  hemoglobin,  of  equal  weight 
and  the  same  age,  will  often  not  return  to  the  normal  at  any- 
thing like  the  same  rate. 


TREATMENT. 


231 


Blood. — The  blood  charts  shown  below  are  selected  from 
those  published  by  Ashford  and  King,  and  some  of  oar  own, 
to  show  the  rate  of  improvement  in  the  blood  during  treat- 
ment. It  will  be  noted  in  most  of  the  charts  that  the  num- 
ber of  red  cells  increases  faster  than  the  hemoglobin,  and 
that  they  usually  go  considerably  above  the  normal 
5,000,000  long  before  the  hemoglobin  has  reached  normal. 
It  will  also  be  noted  that  the  eosinophiles  come  down  more 
slowly  than  the  gain  in  red  cells  or  hemoglobin.  In  fact, 
they  often  remain  high  after  the  blood  is  otherwise  normal. 
"We  know  of  several  instances  in  which  the  eosinophile  count 
has  been  above  6  percent  six,  eight,  and  ten  months  after 
all  worms  were  expelled,  and  one  instance  of  17  percent  two 
years  after  successful  anthelmintic  treatment. 

It  may  occur,  as  is  shown  in  chart  4,  that  the  eosinophiles 
may  increase  for  some  time  as  the  blood  improves,  espe- 
cially in  those  severe  cases  in  which  the  stimulus  is  suf- 
ficiently great  to  exhaust  the  eosinophile-making  ability, 
which  again  revives  after  a  part  of  the  worms  are  gotten 
rid  of. 


CHART  2. 

Date.  Hemoglobin.       Red  cells.           White  cells. 

May       8 33  2,868,000  13,200 

May     16 36  2,991,040                 5,000 

May     23 38  3,960,000                 5,200 

May     30 36  4,384,000'               3,200 

June       6 50  4.000,000                 9.200 

June    13 56  4,541,600  .5,200 

June     20 62  4,360.000                  9.800 

June     27 67  5,261,600                 7,200 

July       4 66  4,152,800                 8,800 

July     11 76  6,866,400                  6,400 

July     18 83  7,635,200                  6,200 

July     25 83  7,035,200                  7,400 

Aug.       1. 82  5,176,000                  4.000 

Aug.       8 75  5,924,000                  5,000 

Aug.     15 101  5,164,000                 7,800 


Eosinophiles. 
16.8 
22.4 
16.4 
17.6 

8.6 
14.8 
10.8 

8.8 

9.0 

6.0 

4.8 
5.6 
8.6 


232 


HOOKWORM  DISEASE. 


Date. 


May 

17 

May 

24 

May' 

31 

June 

7 

June 

14 

June 

21 

June 

28 

July 

4 

July 

21 

Aug. 

2 

Aug. 

3 

Aug. 

4 

Aug. 

6 

CHART  3. 

loglobi 

in.       Red  cells. 

White  cells. 

lOcisiiioijliiles. 

28 

3,480,000 

7,400 

10. 

29 

3,024,000 

7,200 

8. 

30 

3,864,000 

5,000 

8.8 

50 

3,981,600 

11,600 

4. 

54 

5,786,400 

4,200 

8.8 

66 

5,355,200 

5,800 

10,4 

90 

6,195,200 

6,400 

12. 

103 

6,088,000 

17,800 

6.4 

115 

95 

7.2 

92 

8.8 

92 

6.4 

85 

6. 

CHART  4. 


Date.  Hemoglobin.       Red  cells. 

May     12 20  3,195,520 

May     19 28  2,804,000 

June    26 38  4,075,620 

June      2 38  4,626,400 

June      9 41  5,901,600 

June    16 46  5,817,600 

June     23 49  6,016,000 

July     30 55  5,964,000 

July       7 67  6,466,400 

July     14 76  6,295,200 

July     21 82  6,017,600 

Aug.     28 83  6,364,000 

Aug.       4 90  6,630,400 

Aug.       4 104  6,724,000 


White  cells. 

Eosinophiles. 

6,400 

.8 

5,000 

4.8 

3,400 

6.8   ■ 

3,800 

4.8 

4,400 

4. 

4,400 

7.2 

5,000 

8. 

6,400 

21.2 

7,600 

12.2 

11,200 

9.2 

6,600 

9.6 

4,400 

8. 

8,800 

2.2 

7,800 

1.6 

CHART  5. 

Date. 

Hemos'lob 

in.       Red  cells. 

White  cells. 

Eosinophiles. 

May     13 

27 

2,306,640 

6,200 

2. 

May     20 

19 

1,688,000 

5,000 

.4 

May     27 ... . 

25 

1,804,000 

3,800 

4.1 

June      7 . .  . . 

27 

2,964,000 

4,800 

July     13 ... . 

30 

2,977,600 

8,600 

.8 

TREATMENT. 


23: 


CHART  6. 

Date.  Hemoglobin.       Red  cell.s.           White  cells.    Eosinopliiles. 

May     13 14  1,226,400  4,200  8.4 

May     20 21  1,746,640  5,000  4.4 

May     27 21  2,084,400  5,600  2.8 

June      3 22  2,504,000  4,000  3.2 

June    10 22  2,377,600  3,600  2.4 

June     17 32  2,555,200  2,800  3.2 

June    24 ,  52  4,461,600  4,200  3.2 

July        1 41  3,528,800  4,200  2.8 

July       8 65  4,870,400  8,200  1.2 

July      15 78  4,852,800  4,200  5.6 

July      22 78  4,352,000  5,600  3.2 

July     29 68  4,417,600  6,200  3.2 

Aug.       7 95  5,092,800  8,200  4.8 

Aug.     14 109  5,190,400  10,800  2. 


CHART  7. 


Date.  Hemoglobin.       Red  cells. 

May     14 16  1,531,200 

May     21 31  2,133,280 

May     28 27  2,666,400 

June      4 35  3,880,000 

June    11 36  3,315,200 

June    18 50  4,181,600 

June    25 59  5,238,400 

July       2 56  5,288,800 

July       9 55  5,195,200 

July     17 64  5,461,600 

July      23 64  5,786,400 

July     30 84  5,440,000 

Aug.       6 .  90  6,688,000 

Aug.     14 101  5,928,800 


White  cells.    Eosinophiles. 


7,800 
6,200 

11,600 
9,800 
7,400 

14,800 

11,200 
7,400 

11,200 
8,600 
4,800 
9,600 
6,800 

10,200 


18.3 

14.4 

18.4 

28.4 

22. 

17.2 

46. 

22. 

32.4 

40. 

18. 

24.4 

26. 

28.4 


Date.  Hemoglcbin 

Nov.  14 25 

Nov.  22 35 

Nov.  28 50 

Dee.   8 65 

Dec.  15 65 


CHART  8. 

n.       Red  cells. 

White  cells. 

Eosinophiles. 

2,457,500 

5,035 

16. 

2,987,500 

3,050 

12. 

3,603,125 

2,431 

21. 

4,050,000 

2,083 

20. 

5,005,600 

3,024 

18. 

234 


HOOKWORM  DISEASE. 


CHART  9. 

Age  14.    Thymol  once  a  week,  no  iron. 

Date.                                Hemoglobin.  Red  cells.                 Eo.sinophiles. 

May    19 34  3,671,400  19. 

May"*  26 45  4,430,000  14. 

June     2 61  

June     9 60  5,200,000  6. 

June   16 63  5,904,000  9. 

June    23 82                         6. 

June    30 100  5,409,500  8. 


CHART  10. 

Age  32.     Thymol.     Cured  of  worms  after  two  treatments.     Blaud's  pills. 

Date.                                Hemog-lobin.  Red  cells.  Eosinophiles. 

Nov.    19 72  4,950,000  12. 

Nov.    26 78  6. 

Dec.    19 85  5,640,000  10. 

Dec.     28 104  6,120,000  4. 


CHART  11. 

Age  16.     Mild  case.     Thymol.     Cured  first  course.     No  iron. 
81  woi'ms  collected. 

Date.  Hemoglobin.  Red  cells.  Eosinophiles. 

March      6 86  5,100,000  4. 

March  19 94  6,244,000  4. 

April        2 96  5,450,000 


CHART  12. 

Age  17,  female.     Thymol.     Mild  infection,  pernicious  anemia  type.     Fow- 
ler's solution  after  first  two  weeks.     History  indicates  hookworm 
disease  all  her  life. 

Date-  Hemoglobin.  Red  cells.  Eosinophiles. 

March    13 55  2,340,000  6. 

March    29 51  2,422,000  3. 

May  3 63  3,215,000  6. 

June        4. 

.Tune       19 61  4,752,000  4. 

Sept.       22 88  5,420,000 


TREATMENT.  235 

This  case  illustrates  the  slow  (seven  months)  improve- 
ment usually  made  by  this  kind  of  anemia..  Chart  1  shows 
another  case  of  this  kind,  in  which  it  took  nearly  two  years 
for  the  blood  to  become  approximately  normal.  Though 
severe  cases  may  require  several  months  to  return  to  a 
normal  blood  condition,  it  is  our  belief  that  the  average  case 
in  this  country  reaches  a  normal  red  cell  count  and  hemo- 
globin index  in  one  to  three  months,  and  very  many  mild 
cases  within  one  month. 

Height  and  weight. — The  growth  in  height  is  in  propor- 
tion to  the  amount  of  reduction  and  the  age  of  the  patient. 
When  patients  are  not  more  than  two  or  three  inches  below 
what  they  should  be,  this  is  usually  gained  if  they  are  not 
over  20  years  old.  When  over  20  they  may  still  grow,  but  it 
is  doubtful  whether  they  ever  reach  the  height  due  them. 
In  fact,  we  have  seen  many  cases  grow  several  inches  in 
height  and  several  pounds  in  weight  after  they  were  26  to  28 
years  old.  One  man  27  years  old  married  while  yet  a  boy 
in  size  and  appearance,  and  moved  to  town.  Within  a 
couple  of  years  he  had  grown  so  much  that  it  was  often 
remarked  that  married  life  had  made  a  man  of  him.  This 
occurred  before  we  knew  of  hookworm  disease,  but  subse- 
quent familiarity  with  the  disease  and  an  opportunity  to 
examine  the  man's  brother,  and  the  knowledge  that  another 
brother  had  died  of  undoubted  hookworm  disease,  explain 
the  cause  of  his  dwarfing.  The  gain  in  weight  is  even 
more  rapid  sometimes  than  the  gain  in  height.  A  16-year 
old  boy  under  our  observation  gained  twenty  pounds  in 
weight  and  grew  two  inches  taller  in  two  months.  Captain 
J.  F.  Siler  had  one  patient  who  gained  thirty-five  pounds 
in  one  month.  The  foregoing  were  severe  infections,  but 
we  have  often  seen  remarkable  gains  in  weight  and  general 
feeling  by  patients  who  had  very  mild  infections.  One 
man  gained  nine  pounds  in  one  month  after  expelling  only 


236  HOOKWORM  DISEASE. 

nineteen  worms.  Another  man,  35  years  old,  gained  nine- 
teen pounds  after  getting  rid  of  a  mild  infection. 

Patients  with  severe  disease  and  childish  voices  at  18  to 
20  or  22  years  old  will  usually  have  change  of  voice  within 
two  or  tliree  months. 

Pubic  and  axillary  hair  that  have  not  started  begin  to 
grow  within  two  or  three  months  if  the  patient  is  of  proper 
age.  We  have  observed  the  beard  to  begin  to  grow  at  29 
years,  and  we  believe  it  may  later  than  this. 

The  mammae  of  girls  develop  rapidly  in  dwarfed  patients, 
and  we  have  observed  this  after  24.  No  doubt  this  can 
occur  even  later  if  the  worms  are  gotten  rid  of. 

At  the  end  of  our  chapter  on  treatment  we  wish  to  em- 
phasize that  we  must  not  lose  sight  of  any  other  diseases 
the  patient  may  have  when  we  are  considering  his  treat- 
ment. Curing  hookworm  disease  may  often  benefit,  but 
will  not  cure,  other  diseases  present. 


REFERENCES. 


Affleck,  27 

Agramonte,  37 

Allesandrini,  106 

Allyn,  29 

Alvarez,  37 

Annett,  68 

Aporto,  113 

Arnold,  31 

Arslan,  113 

Ashford,   31,  32,   59,   83,  93,   94, 

132,   135,    151,   165,   172,    184, 

209,    220,    222,    224 
Austregesilo,  153 

Baelz,  36 

Bagly,  37 

Bartlett,  27 

Bass,   38.   39,  70,   92,   145,   146, 

175,  177,  203 
Baumler,  23 
Behrend,  29 
Belger,  67,  201 
Bentley,  79,  140,  203,  222 
Bilharz,  22,  100 
Blaud,  228 
Blickhahn,  29 
Bondurant,  38 
Boston,  29 

Boycott,  34,  65,  179,  200,  201 
Bozzolo,  22,  49,  212 
Branch,  41,  42 
Brims,  202,  209,  223 
Butterworth,  146 

Calmette,  79,  201 
Castiglioni,  22 
Chabert,  24 
Chamberlain,  39 
Claytor,  29,  37 
Cobbold,  49 
Colbert,  222 
Cole,  38,  40 
Colomiatti.  22 
Concato,  22 
Craig,  96 
Creplin,  49 
Crisafuli,  113 

Dabney,  29 


97, 
203, 


167, 


Dalgetty,  203 

Daniels,  95 

Da  Silva  Pinto,  41 

Deaderick,  39,  43 

Dieminger,  166 

Diesing,  49 

Dobson,  36 

Dock,  127 

Dolley,  28 

Drake,  27 

Dubini,  20,  21,  48,  49 

Duncan,  25 

Dyer,  29 

Edwards,  19 
Elliott,  144 
Ernst,  102 
Swing,  186 

Fearn'side,  99 
Firket,  34 
Ford,  227 
Fort,  38 
Frankel,  29 
Frolich,  21,  48,  49 
Fiilleborn,  41,  184 

Gabbi,  106 

Gage,  38,  39,  138,  177,  217 
Galli-Valerio,  67,  69 
Geddings,  25 
Giles,  68,  212 
Goldmann,  106,  202 
Goldsmith,  36 
Gotuzzo,  153 
Goze,  21,  49 
Grassi,  22,  77,  165 
Griesinger,  22 
Guthrie,  38 
Gutierrez,  37,  59,  96 

Haldane,  34,  65,  179,  200,  201 
Hall,  29 

Hammerschmid,  20 
Harris.  38 
Harrison,  38 
Henry,  50 
Herff.  29 
Hermann.  67,  79 


238 


REFERENCES. 


Heusinger,  27 
Hirsch,  24 

Immermann,   23 

King,  32,  59,  83,  93,  94,  97,  132,  135, 
151,  165,  172,  184,  203,  209,  220, 
222,  224 

Kinyoun,  38 

Kiilz,  35,  171 

Labat,  19 

Lambinet,  65,  79,  202,  209,  210,  223 

Leichtenstern,  23,  43,  67,  70,  75,  99, 

102,  136,  165,  209,  212,  224 
Leidy,  28 
Leiper,  41,  68 
Lemann,  38,  127 
Leuckhart,  23,  49,  59 
Liefmann,  105 
Lindeman,  214 
Loeb,  104 
Looss,  32,   41,  49,  60,   67,  69,   70,   75, 

99,  102,  108,  110,  138,  164,  172,  209 
Lussana,  113 

Lutz,  59,  60,  144,  151,  211,  212 
Lyell,  25 

McConnell,  36 
McGehee,  149 
MacDonald,  153 
Maliverria,  22 
Malvoz,  202 
Manouvriez,  201 
Manson,  155,  212 
Manuel,  37 
Mathias,  36 
Menche,  151 
Mink,  56 
Molin,  49 
Mohlau,  29 
Mosler,  212 

Neumann,  225 
Nichols,  42 
Nicholson,  38 
Nieden,  151 
Noc,  41 
Noe,  77 

Oliver,  35,  67,  69,  202 
Oppenheim,  153 
Ozzard,  68 

Paletti,  22 
Parona,  22,  165 
Peipper,  212 
Pepper,  158,  171 
Perner,  67 


Perroncito,  22,  62 
Perry,  38 
Philbrick,  195 
Pieri,  63,  69,  77 
Piso,  19 
Pitt,  24 
Posnett,  36 
Preti,  106,  108 
Previtera,  33 
Prowe,  37 
Pruner,  22 

Railliett,  50 
Rankin,  38 
Romani,  38 
Ross,  68 

Sandwith,  97,  211,  212,  228 

Sangalli,  108 

Schaeffer,  30 

Schaudinn,  79 

Scheube,  212 

Schifone,  41 

Schneider,  49 

Schuffner,  69,  79 

Signorelli,  152 

Siler,  39 

Smith,  Allen   J.,   29,   39,   60,   65,  97, 

104,  111 
Smith,  Claude  A.,  38,  63,  70,  79,  138, 

144,  170,  172 
Scare,  154 
Sonderegger,  22 
Stiles,   21,  30.   37,  40,  42,  49,   59,   75, 

156,  167,  178,  186,  228 

Tebault,  29 

Telemann,  171 

Tenholt,  42,  67,  79,  97,  156,  203,  223 

Toth,  202,  223 

Turner,  42 

Vadala,  106 
Van  Durne,  138 
Vannini,  113 
Von  Linstow,  59,  63 
Von  Siebold,  22,  49 

Wainwright,  42 

Warfield,  38 

Weiss,  186 

Whipple,  37.  97,  99,  102,  108,  111 

Winthrop,  38,  40 

Wood,  27 

Wucherer,  22,  60 

Yates,  29,  96,  112 
Yoshida,  148 


INDEX. 


Acute  cases  of  hookworm   disease, 

134 
Administration  of  thymol,  mode  of, 
in  treatment,  213 
pregnancy  contraindicates,    218 
Africa,  hookworm  disease  in,  35 
Agchylostoma    as    name    for    hook- 
worm, 21 
Age  as  a  factor   in  hookworm   dis- 
ease, 230 
Air,  effect  of,  on  ova,  65 
America,    uncinaria    as    name    for 

hookworm  in,  49 
Anatomy,  pathologic,  94 
Anemia,  arsenic  in,  228 

as  a  symptom   in  hookworm   dis- 
ease,  135 
Blaud's  pills  in,  228 
commission  for  study  of,  in  Porto 

Rico,  32 
due  to  dirt  eating,  146 
Dr.  Ford's  iron  and  quinine  pills 

in,  227 
effect  of  iron  in,  228 
Fowler's  solution  in,  228 
in  hookworm  disease.  111 

benefited  by  iron,  226 
Investigations  of,  20 
miner's,  20 
of   secondary   type   in   hookworm 

disease,  226 
progressive,       characteristic       of 

hookworm  disease,  17 
secondary  type  of,  136 
treatment   of,    in   hookworm    dis- 
ease, 225 
Animals,  feces  pass  through   diges- 
tive tract  of,  86 
hookworm  in,  50 

infecting,  70 
ova  scattered  by,  194 
Ankylostoma   duodenale   as   generic 
name  for  hookworm,  49 
as  name  for  hookworm,  17 
description  of,  49 
development  of,  63 
old  world  parasite,  41 
Anthelmintic  treatment,  230 
Antilles,  hookworm   disease  in   the, 
37 


Appearances,  post-mortem,  in  hook- 
worm disease.  See  Post-mor- 
tem appearance  of  hookworm 
subject. 

Appendix  vermiformis,  hookworm 
in,  149 

Appetite  in  hookworm  disease,  146 
perversion  of,  146 

Arabs,  hookworm  disease  among,  43 

Arsenic  in  anemia,  228 

Arteries,  post-mortem  appearance 
of,  95 

Asia,  hookworm  disease  in,  36 

Australia,  hookworm  disease  in,  36 

Austria,  hookworm  disease  in,  33 

Autopsy  of  hookworm  subject,  how 
to  make,  96 

B.ilLKAx    peninsula,    hookworm    dis- 
ease in,  33 
Barefooted      children      exposed     to 

hookworm  disease,  44,  92 
Bass'  method  of  centrifuging,  175 
Belgium,  hookworm  disease  in,  33 
Beriberi,  hookworm  disease  mistak- 
en for,  183 
Beta-naphtol,  dose  of,  in  treatment, 
222 
for  expulsion  of  feces  for  exami- 
nation, 177 
treatment,  222 

hookworms  expelled  in,  223 
Blaud's  pills  in  anemia,  228 

in  treatment,  229 
Blood  charts  in  hookworm  disease, 
229 
in  treatment,  229,  231 
coagulation,  conditions  accelerat- 
ing, 104 
substance  delaying,  105 
feces  contain  traces  of.  149 
larvae  in  the,  82 
post-mortem  appearance  of,  100 
pressure  in  hookworm  disease,  143 
symptoms  of,  135 

of    hookworm    disease    due    to 
loss  of,  115 
test  for,  in  feces,  149 
Blotting  paper   test   for   hookworm 
disease,  178 


239 


240 


INDEX. 


Bohemia,  hookworm  disease  in,  20 
Bone  marrow,  post-mortem  appear- 
ance of,  100 
Brain,   post-mortem   appearance   of, 

100 
Brazil,  hooliworm  disease  in,  22 
Bronchial  tubes,  larvae  in,  82 

Cases,  acute,  of  hookworm  disease, 

chronic,  of  hookworm  disease,  134 
marked,  of  hookworm  disease,  132 
moderate,    of    hookworm    disease, 

132 
slight,  of  hookworm  disease,  132 
Cause  of  hookworm  disease,  17 
Cells,    vegetable,    differentiation    of 

hookworm  ova  from,  169 
Central     America,     hookworm     dis- 
ease in,  37 
Centrifuge,     concentration     of    ova 
with,  172 
preparing  feces  for,  172 
Purdy,  172 
Centrifuges,  172 
Centrifuging,  Bass'  method   of,  175 

method  of,  172 
Certain  diagnosis,  155 
Characteristics    of    hookworm    dis- 
ease, 17 
Charcot-Leyden  crystals  as  guide  in 

prognosis,  185 
Chewing  tobacco  as  remedy  for  dirt 

eating,  147 
Children,     barefooted,     exposed     to 

hookworm  disease,  44,  92 
Chlorosis,  Egyptian,  hookworm  dis- 
ease compared  with,  22 
symptoms,  hookworm  disease  like, 
26 
Chronic  cases  of  hookworm  disease, 
134 
hookworm  disease,   color   of   skin 
in,  141 
Circulatory    system,    symptoms    of, 

17,  142 
Classification  of  hookworm,  49,  50 
Clay  as  a  factor  in  hookworm  dis- 
ease, 43 
Clay  eating,  146 

Climate  a  factor  in  hookworm  dis- 
ease, 42 
Closet.     See  Privy. 
Coagulation,  blood,  conditions  accel- 
erating, 104 
substance  delaying,  105 
Cold,  effect  of,  on  larvae,  202 

on  ova,  63 
Commission  for  study  of  anemia  in 
Porto  Rico,  32 


Concentration  of  ova  with  centri- 
fuge, 172 

Conditions  accelerating  blood  coag- 
ulation, 104 

Constipation  in  hookworm  disease, 
149 

Construction  of  sanitary  privy,  195 

Count,  eosinophile,  in  diagnosis,  178 

Country  schools  not  provided  with 
privies,  91 

Cover  glasses  unnecessary  in  micro- 
scopic examination,  160 

Crystals,  Charcot-Leyden,  as  guide 
in  prognosis,  185 

Cuba,  hookworm  disease  in,  37 

Cure,  hookworm  disease  capable  of, 
17 

Danger  of  hookworm  carriers,  191 
Darkness,  effect  of,  on  ova,  65 
Definition  of  hookworm  carrier,  17 

of  hookworm  disease,  17 
Dermatitis  produced  by  skin  infec- 
tion, 76 
Description   of   ankylostoma  duode- 
nale,  49 
of  hookworm,  50 
of  nematodes,  47 
of  strongylidce,  47 
Desiccation,  effect  of,  on  ova,  64 
Development,  hookworm  disease  re- 
tards, 126 
impaired,   characteristic   of  hook- 
worm disease,  17 
of  ankylostoma  duodenale,  63 
of  larvae,  65 
Dew  poison,  hookworm  in,  79 
Diagnosis,  155 
by     examination     of     stool     after 

treatment,  177 
eosinophile  count  in,  178 
mouth  of  hookworm  feature  for, 
54 
Diarrhea  in  hookworm  disease,  149 
Diet  during  thymol  treatment,  215 
Differentiation  of  embryos  and  lar- 
va3,  165 
of    hookworm    larvae    from    other 

larvae,  168 
of  hookworm  ova  from  other  ova, 

167 
of  hookworm  ova  from  vegetable 
cells,  169 
Digestive  system,    symptoms  of,   in 
hookworm  disease,  17,  144 
tract     of     animals,     feces     pass 
through,  86 
Dirt  eating,  146 
anemia  due  to,  146 
cause  of  worms,  147 


INDEX. 


241 


Dirt  eating — cont'd. 

chewing  tobacco   as    remedy    for, 

147 
infectious,  28 

in  region  of  great  lal^es,  27 
in  United  States,  24 
remedies  for,  147 
symptoms  of,  25 
Dirty  fruit  as  a  factor  in  hookworm 
disease,  45 
vegetables    as    a   factor    in    hook- 
worm disease,  45 
Discharge  of  ova  of  worms  charac- 
teristic of  hookworm  disease 
17 
Discovery  of  hookworms,  20 
Disease,  hookworm.     See  Hookworm 
disease, 
hoolvworm,  a  filth  disease,  192 
symptoms    of    hookworm,    altered 
by  other  diseases,  154 
Diseases,   intercurrent,  and  compli- 
cations, 187 
Disinfectants,  effect  of,  on  larvae,  69 

for  hookworms,  201 
Disinfection  in  mines,  201 
Disposition  of  feces,  86 
in  absence  of  privies,  89 
in  mines,  91 
Distribution    and    economic    impor- 
tance, 33 
Divisions  of  hookworm,  49,  50 
Dose  of  beta-naphtol   in  treatment, 
222 
of  eucalyptus  in  treatment,  224 
of  male  fern  in  treatment,  223 
of  podophyllin  in  treatment,   225 
of  thymol  in  treatment,  212 
Drinking,  excessive,  ova  diminished 
by,  166 
water  as  a  factor  in  infection,  75 
Dropsy  in  hookworm  disease,  150 
Dyspnea,  symptoms  of,  142 

EcDYSis,  first,  of  larvae,  74 

second,  of  larvae,  74 

third,  of  larvae,  85 
Economic  importance  and  distribu- 
tion, 33 
Effect  of  air  on  ova,  65 

of  cold  on  larvae,  202 

of  cold  on  ova,  63 

of  darkness  on  ova,  65 

of  desiccation  on  ova,  64 

of  heat  on  ova.  63 

of  iron  in  anemia,  228 

of  light  on  larvae,  203 

of  oxygen  on  ova,  64 

of  siuilight  on  ova.  65 


Effect — cont'd. 

of  vaseline  on  larvae,  67 
of  water  in  mines,  35 
of  water  on  larvae,  203 
Eggs,  hookworm.     See  Ova. 
Egypt,  hookworm  disease  in,  22,  32 
Egyptian   chlorosis,   hookworm   dis- 
ease compared  with,  22 
Elevation  as  a  factor  in  hookworm 

disease,  43 
Embryology  of  hookworm,  02 
Embryos  and  larvae,  differentiation 

of,  165 
Encysted  stage  of  larvae,  66 
England,  hookworm  disease  in,  33 
Eosinophile  count  in  diagnosis,  178 
Eosinophiles  as  guide  in  prognosis, 
184 
in  hookworm  disease,  136 
Eosinophilia  present  in  worm  infec- 
tions, 180 
Epigastric    pain    in    hookworm   dis- 
ease, 144 
Epithelium    nourishment    for   hook- 
worm, 85 
Eucalyptus,    dose   of,   in   treatment, 
224 
treatment,  224 
Evacuation,  time  for  finding  larvae 

after,  170 
Examination,    beta-naphtol    for    ex- 
pulsion of  feces  for,  177 
kind  of  feces  for,  157 
microscopic,   cover  glasses  unnec- 
essary in,  160 
going  over  slide  in,  164 
light  necessary  for,  163 
magnification  to  be  used  in,  161 
making  preparation  for.  158 
number  of  slides  in,  161 
size  of  slides  in,  159 
time  required  for,  161 
wet  preparation  to  be  used  in, 
161 
obtaining  feces  for,  157 
of  feces  for  ova.     See  Ova. 
of  stool,  diagnosis  by,  after  treat- 
ment, 177     ■ 
thymol  for  expulsion  of  feces  for, 
177 
Excessive  drinking,  ova  diminished 

by,  166 
Experiments  with  larvae,  138 
Expulsion  of  feces,  beta-naphtol  for, 
for  examination,  177 
thymol  for.  for  examination,  177 
Extermination     of     hookworms     in 

prophylaxis,  190 
Eyes,  symptoms  of,  151 


242 


IXDEX. 


Favokabie   prognosis  in  proportion 

to  treatment,  188 
Fatal    cases    of    hookworm    disease, 

127 
Fatality,    occasional,    of    hookworm 

disease,  17,  19 
Feces,  beta-naphtol  for  expulsion  of, 
for  examination,  177 
containitraces  of  blood,  149 
disposition  of,  86 
in  absence  of  privies,  89 
in  mines,  91 

examining,  for  ova.     See  Ova. 
hatching  of  ova  in,  by  mixture,  72 
kind  of,  for  examination,  157 
obtaining,  for  examination,  157 
of  infected  persons  source  of  in- 
fection, 93 
pass    through    digestive    tract    of 

animals,  86 
preparing,  for  centrifuge,  172 
quantity    of,    passed    varies    with 

conditions,  166 
test  for  blood  in,  149 
thymol   for   expulsion  of,   for   ex- 
amination, 177 
Flies,  hatching  of  ova  promoted  by, 

72 
Food  as  a  factor  in  infection,  76 

in  prognosis,  182 
Ford's,  Dr.,   iron  and  quinine  pills 

in  anemia,  227 
Fowler's  solution  in  anemia,  228 
France,  hookworm  disease  in,  20,  33 

Gain  in  height  after  treatment,  235 

in  weight  after  treatment,  235 
Gastric     secretions,     investigations 

of,  148 
General     treatment     of     hookworm 

disease,  225 
Generic  name  for  hookworm,  ankyl- 

ostoma  duodenale  as,  49 
Genito-urinary     system,     symptoms 

of,  150 
Germany,  hookworm  disease  in,  33 
Glands,     hemolymph,     post-mortem 
appearance  of,  100 
male  sexual,  of  hookworm,  57 
mesenteric,    post-mortem    appear- 
ance of,  100 
Grades  of  hookworm  disease,  132 
Great  lakes,  dirt  eating  in  regions 

of,  27 
Greek  derivation  for  hookworm,  21 
Ground  itch,  91,  137 

origin  of  hookworm  infection,  205 
percentage  of,  93 
treatment  of,  207 
Guam,  hookworm  disease  in,  36,  79 


HaakeiXwurji     proposed     as     name 

for  hookworm,  21 
Hatching  of  ova   in   feces   by   mix- 
ture, 72 
of  ova,  moisture  as  a  factor  in,  74 
of  ova  promoted  by  flies,  71 
of  ova,  requirements  for,  71 
of  ova,  shade  as  a  factor  in,  74 
Hawaiian    Islands,    hookworm    dis- 
ease in,  36 
Heart,  lavvee  in  the,  82 

post-mortem  appearance  of,  94 
Heat,  effect  of,  on  ova,  63 
Height    and    weight    in    hookworm 
disease,  235 
gain  in,  after  treatment,  235 
Hemoglobin     estimation     in     hook- 
worm disease,  135 
Hemolymph      glands,     post-mortem 

appearance  of,  100 
Hemolysis  in  hookworm  disease,  107 
Hemolytic  toxins  in  hookworm  dis- 
ease, 106 
Hemorrhage,  hookworm  causes,  102 
hookworm    causes    greater,    than 
necessary  for  food,  104 
Hemorrhages,    ratio   of,   to    number 

of  hookworms,  99 
History  of  hookworm,  19 
Hookworm,   agchylostoma  as   name 
for,  21 
ankylostoma   duodenale    as   name 

for,  17 
ankylostoma  duodenale  as  generic 

name  for,  49 
a  parasite,  17 

barefooted  children  exposed  to,  92 
belongs  to  family  strongylidse,  46 
to  nematode  class,  46 
to  sub-family  strongylinse,  46 
carrier,  danger  of,  191 
definition  of,  17 

has  mild  case  of  hookworm  dis- 
ease, 119 
causes  hemorrhage,  102 

greater  than  necessary  for  food, 
104 
classification  of,  49,  50 
description  of,  50 
differentiation     of,     larvpe     from 

other  larvse,  168 
discovery  of,  20 
disinfectants  for,  201 
divisions  of,  49,  50 
eggs.     See  Ova. 
embryology  of,  62 
epithelium  nourishment  for,  85 
eradication,   requirements   of,  191 
Greek  derivation  for,  21 


INDEX. 


243 


Hookworm — cont'd. 

haakenwurm    proposed    as    name 
for,  21 

history  of,  19 

infecting  animals,  70 
man,  70 

infection,    cause     of    greater,     in 
tropics,  75 
ground  itch  origin  of,  205 
relation  of  moisture  to,  43 

in  animals,  50 

in  appendix  vermiformis,  149 

in  dew  poison,  79 

in  ground  itch,  79 

in  Porto  Rico,  30 

in  small  intestine,  97 

in  the  South,  30 

in  toe  itch,  79 

in  water  sore,  79 

larvae,     differentiation     of,     from 
other  larv£e,  168 

male  sexual  glands  of,  57 

miner's  anemia  due  to,  23 

mouth  of,  feature  for  diagnosis,  54 

mucosa  normal  food  of,  108 

mucus  essential  for,  20 

necator  Americanus  as  name  for, 
17 

new  world,  30 

old  world,  30 

ova,  58 

description  of,  164 
differentiation    of,    from    other 

ova,  167 
differentiation  of,  from  vegeta- 
ble cells,  169 

origin  of  scientific  name  for,  21 

scientific  name  of,  17 

subject,  how  to  make  autopsy  of, 
96 

subject  may  present  no  recogniz- 
able symptoms,  116 

subject,    post-mortem    appearance 
of,  94 

sucking  an  important  function  of, 
102 

synonyms  for,  18,  47 

toxin  caused  by.  111 

treatment,  other  drugs  in,  225 

treatment,   other  methods  of,  222 

ulcers  caused  by.  111 

unclnaria  as  name  for,  in  Amer- 
ica, 49 

vmcinaria  duodenalis  as  name  for, 
17 

uteri  of,  57 

zoologic  features  of,  46 
Hookworms  expelled  in  beta-naphtol 
treatment,  223 


Hookworms — cont'd. 

expelled  in  thymol  treatment,  223 

extermination  of,  in  prophylaxis, 
190 

number  of,   indicated  by  number 
of  ova  in  feces,  165 

ratio  of  hemorrhages  to   number 
of,  99 

results  from  thymol  in  expellina-, 
220 

treatment  of,  in  intestine,  210 

when,  cease  to  ovulate,  167 
Hookworm    disease   a   filth    disease, 
192 

acute  cases  of,  134 

age  as  a  factor  in,  230 

among  Arabs,  43 

anemia  as  symptom  in,  135 

anemia  in.  111 

benefited  by  iron,  226 
of  secondary  type  in,  226 

appetite  in,  146 

barefooted  children  exposed  to,  44 

blood  charts  in,  229,  231 

blood  pressure  in,  143 

blotting  paper  test  for,  178 

capable  of  cure,  17 

cause  of,  17 

causes  laziness,  124 

characteristics  of,  17 

characterized  as  lazy  disease,  152 

chronic  cases  of,  134 

clay  as  a  factor  in,  43 

climate  a  factor  in,  42 

color  of  skin  in  chronic,  141 

compared    with    Egyptian   chloro- 
sis, 22 

constipation  in,  149 

definition  of,  17 

diarrhea  in,  149 

dirty  fruit  as  a  factor  in,  45 

dirty  vegetables  as  a  factor  in,  45 

discharge  of  ova  of  worms  char- 
acteristic of,  17 

divisions  of  types  of,  130 

dropsy  in,  150 

effect  of,  on  duration  of  life,  186 

elevation  as  a  factor  in,  43 

eosinophiles  in,  136 

epigastric  pain  in,  144 

eyes  in,  151 

fatal  cases  of,  127 

general  treatment  of,  225 

genito-urinary  system  in,  150 

grades  of,  132 

height  and  weight  in,  235 

hemoglobin  estimation  in,  135 

hemolysis  in,  107 

hemolytic  toxins  in,  106 


244 


IXDEX. 


Hookworm  disease — cont'd, 
home  of,  in  tropics,  23 
hookworm     carriers     liave     mild 

cases  of,  119 
impaired    development    character- 
istic of,  17 
in  Africa,  35 
in  Asia,  36 
in  Australia,  36 
in  Austria,  33 
in  Balkan  peninsula,  33 
in  Belgium,  33 
in  Bohemia,  20 
in  Brazil,  22 
in  Central  America,  37 
in  Cuba,  37 
in  Egypt,  22,  32 
in  England,  33 
in  France,  20,  33 
in  Germany,  23,  33 
in  Guam,  36 
in  Hawaiian  Islands,  36 
in  Hungary,  20,  33 
in  Italy,  22,  33 
in  Mexico,  29,  37 
in  New  Guinea,  36 
in  Panama,  37 
in  Philippines,  36 
in  Sardinia,  33 
in  Servia,  33 
in  Sicily,  33 
in  Spain,  33 
in  Switzerland,  23 
in  the  Antilles,  37 
in  the  South,  28 
in  United  States,  24,  37 
lactation  imperfect  in,  186 
lactation  in,  150 
leucocytes  in,  136 
like  chlorosis  symptoms,  26 
marked  cases  of,  132 
mild  type  of,  122 
mines  a  factor  in,  42 
mistaken  for  beriberi,  183 

for  malaria,  183 

for  nephritis,  183 

for  tuberculosis,  183 
moderate  cases  of,  132 
mortality  of,  184 
nervous  system  in,  152 
occasionally  fatal,  17,  19 
occupation  as  a  factor  in,  44 
other  parasites  in,  188 
perforation  of  intestine  in,  188 
persons  exposed  to,  17 
perversion  of  appetite  in,  146 
perversions  in,  153 
pneumonia  intercurrent  in,  187 


Hookworm  disease — cont'd, 
post-mortem  appearances  in.     See 
Post-mortem     appearance    of 
hookworm  subject, 
progressive  anemia  characteristic 
of,  17 
■     psychic  effects  in,  153 
pulse  in,  143 
range  of  latitude  of,  33 
retards  development,  126 
sandy  soil  as  a  factor  in,  43 
sections  where,  occurs,  17 
severe  type  of,  125 

how  recognized,  127 
sexual  perversions  in,  153 
shade  as  a  factor  in,  43 
slight  cases  of,  132 
social  position  as  a  factor  in,  44 
spread  of,  23 

stricture  of  intestine  in,  188 
symptoms  in.     See  Symptoms, 
symptoms  of,  17 

altered  by  other  disease,  154 
circulatory  system  in,  17 
digestive  system  in,  17 
due  to  loss  of  blood,  115 
due  to  toxin,  115 
nervous  system  in,  17 
treatment  of  anemia  in,  225 
uncinaria  as  name  for,   in  Amer- 
ica, 49 
urine  in,  150 
Hungary,     hookworm     disease     in, 
20,  33 

Impaired    development    characteris- 
tic of  hookworm  disease,  17 
Improvement  after  treatment,  229 
Infection,  drinking  water  as  a  fac- 
tor in,  75 
during  rainj^  weather,  92 
eosinophilia  present  in  worm,  180 
feces    of   infected   persons   source 

of,  93 
food  as  a  factor  in,  76 
hookworm,    cause    of    greater,    in 
tropics,  75 
ground  itch  origin  of,  205 
relation  of  moisture  to,  43 
modes  of,  70 
mouth,  69,  70 

prevention  of,  by  larvae,  203 
of  soil,  in  prophylaxis,  192 
privies  source  of,  86 
skin,  69 

by  larvae-containing  water,  45 
only  practical  mode,  93 
stage  of  larvae,  70 


INDEX. 


245 


Infection — cont'd, 
through  skin,  76 
through  wet  shoes,  92 
Intercurrent  diseases  and  complica- 
tions, 187 
Intestinal    canal,    ova    not    hatched 

in,  70,  71 
Intestine,    perforation    of,    in    hook- 
worm disease,  188 
small,  hookworm  in,  97 
stricture  of,  in  hookworm  disease, 

188 
treatment  of  hookworms  in,  210 
Intestines,  post-mortem   appearance 

of,  96,  100 
Intoxication  symptoms,  thymol,  216 

treatment  of  thymol,  219 
Investigations  of  anemia,  20 
of  gastric  secretions,  148 
Iron  and  quinine  pills,  Dr.  Ford's, 

in  anemia,  227 
Iron,   anemia  in  hookworm   disease 
benefited  by,  226 
effect  of,  in  anemia,  228 
Italy,  hookworm  disease  in,  22,  33 

Joints,  symptoms  of,  137 

Keenig's  sign,  152 
Kidneys,     post-mortem     appearance 
of,  95 

Lactation    imperfect   in  hookworm 
disease,  186 

in  hookworm  disease,  150 
Larvae  and  embryos,  differentiation 

of,  165 
Larvae-containing  water,  skin  infec- 
tion by,  45 
Larvae,  development  of,  65 

differentiation    of    embryos    and, 
165 

differentiation  of  hookworm,  from 
other  larvae,  168 

effect  of  cold  on,  202 

effect  of  disinfectants  on,  69 

effect  of  light  on,  203 

effect  of  vaseline  on,  67 

effect  of  water  on,  67,  203 

encysted  stage  of,  66 

experiments  with,  138 

first  ecdysis  of,  74 

infectious  stage  of,  70 

in  the  blood,  82 

in  the  bronchial  tubes,  82 

in  the  heart,  82 

in  the  lungs,  82 

moults  in  development  of,  66 

prevention  of  infection  by,  203 


Larvae — cont'd, 
second  ecdysis  of,  74 
temperature    most    favorable    for, 

42 
third  ecdysis  of,  85 
time  for  finding,  after  evacuation, 

170 
will  penetrate  leather,  206 
Latrine.     See  Privy. 
Laziness,  hookworm  disease  causes 

124 
Lazy     disease,     hookworm     disease 

characterized  as,  152 
Leather,  larvae  will  penetrate,  206 
Leucocytes    in    hookworm    disease, 

136 
Life,  effect  of  hookworm  disease  on 

duration  of,  186 
Light,  effect  of,  on  larvae,  203 

necessary  for  microscopic  exami- 
nation, 163 
Liver,    post-mortem    appearance    of, 
95 
symptoms  of,  141 
Lungs,  larvae  in  the,  82 
post-mortem  appearance  of,  95 

Magnification  to  be  used  in  micro- 
scopic examination,  161 
Making  preparation  for  microscopic 

examination,  158 
Malaria,  hookworm  disease  mistak- 
en for,  183 
Male  fern,  dose  of,  in  treatment,  223 
treatment,  223 
sexual  glands  of  hookworm,  57 
Man,  hookworm  infecting,  70 
Marked  cases  of  hookworm  disease, 

132 
Mesenteric  glands,  post-mortem  ap- 
pearance of,  100 
Method,  Bass',  of  centrifuging,  175 
of  centrifuging,  172 
Pepper's,  for  finding  ova,  171 
Telemann'iS,  for  finding  ova,  171 
Methods,  other,  in  hookworm  treat- 
ment, 222 
special,  for.  finding  ova,  171 
Mexico,  hookworm  disease  in,  37 
Microscopic     examination,     cover 
glasses  unnecessary  in,  160 
going  over  slide  in,  164 
light  necessary  for,  163 
magnification  to  be  used  in,  161 
making  preparation  for,  158 
number  of  slides  in,  161 
size  of  slides  in,  159 
time  required  in,  161 
wet  preparation  to  be  used  in,  161 


246 


INDEX. 


Miner's  anemia,  20 

due  to  hookworm,  23 
Mines  as  factor   in  hooliworm   dis- 
ease, 42 
disinfection  in,  201 
disposition  of  feces  in,  91 
effect  of  water  in,  35 
Mixture,    iiatcliing  of   ova   in   feces 

by^72 
Mode   of   administration   of   thiymol 
in  treatment,  213 
of  infection,  70 
Moderate    cases    of   hool^worm    dis- 
ease, 132 
Moisture  as  a  factor  in  hatching  of 
ova,    74 
relation    of,    to    hool^worm    infec- 
tion, 43 
Mortality  of  hookworm  disease,  184 
Moults  in  development  of  larvae,  65 
Mouth  infection,  69,  70 

of  hookworm  feature  for  diagno- 
sis, 54 
Mucosa  normal  food  of  hookworm, 
108 
post-mortem  appearance  of,  97 
Mucus  essential  for  hookworm,  20 

Necatoe    Americanus    as    name    for 
hookworm,  17 
description  of,  59 
is  new  world  parasite,  41 
synonyms  for,  59 
Nematode  class,  hookworm  belongs 

to,  46 
Nematodes,  description  of,  47 
Nephritis,    hookworm    disease    mis- 
taken for,  183 
Nervous    system,    symptoms    of,    in 
hookworm  disease,  17,  151,  152 
New  Guinea,  hookworm  disease  in, 

36 
New  world  hookworm,  30 

parasite  is  necator  Americanus,  41 
Number  of  hookworms  indicated  by 
number  of  ova  in  feces,  165 
of  slides  in  microscopic  examina- 
tion, 161 

Occupation    as    a    factor    in    hook- 
worm disease,  44 

Old  world  hookworm,  30 

parasite    is    ankylostoma    duode- 
nale,  41 

Organs,    symptoms  on   part   of   cer- 
tain, 135 

Origin      of      hookworm      infection, 
ground  itch,  205 


Other    drugs    in    hookworm    treat- 
ment, 225 
methods  of  hookworm  treatment, 

222 
parasites    in    hookworm    disease, 

188 
Ova  absent  after  thymol  treatment, 

166 
concentration  of,  with  centrifuge, 

172 
description  of  hookworm,  164 
differentiation  of  hookworm,  from 

other  ova,  167 
differentiation  of  hookworm,  from 

vegetable  cells,  169 
diminished  by  excessive  drinking, 

166 
effect  of  air  on,  65 
effect  of  cold  on,  63 
effect  of  darkness  on,  65 
effect  of  desiccation  on,  64 
effect  of  heat  on,  63 
effect  of  oxygen  on,  64 
effect  of  sunlight  on,  65 
hatching  of,  in  feces  by  mixture, 

72 
moisture  as  a  factor  in  hatching 

of,   74 
not   hatched    in    intestinal    canal, 

70,   71 
number    of   hookworms    indicated 

by  number  of,  in  feces,  165 
number  of,  passed  in  stool,  71 
of  hookworm,  58 
of  uncinaria  Americana,  65 
of  uncinaria  duodenalis,  65 
of  worms,  discharge  of,  character- 
istic of  hookworm  disease,  17 
Pepper's  method  for  finding,  171 
present    after    thymol    treatment, 

166 
requirements  for  hatching  of,   71 
scattered  by  animals,  194 
shade  as  a  factor  in  hatching,  74 
special  methods  for  finding,  171 
Telemann's    method    for    finding, 

171 
treatment  before,  appear  in  stool. 

209 
Ovulate,  when  hookworms  cease  to, 

167 
Oxygen,  effect  of,  on  ova,  64 

Panama,  hookworm  disease  in,  37 

two  kinds  of  hookworm  in,  37 
Pancreas     post-mortem    appearance 

of,  96 
Parasite,  hookworm  a,  17 


IXDEX. 


247 


Parasite — cont'd, 
new  world,  is  necator  Americanus, 

41 
old  world,  is  ankylostoma  duode- 
nale,  41 
Parasites,  other,   in  hookworm   dis- 
ease, 188 
other  than  hookworms,  100 
Pathologic  anatomy,  94 
Pathology,  94,  101 
Patient    to    remain    in    bed    during 

thymol  treatment,  215 
Philippines,    hookworm    disease    in, 

36 
Pepper's  method  for  finding  ova,  171 
Percentage  of  ground  itch,  93 
Perforation    of    intestine    in    hook- 
worm disease,  188 
Persons   exposed  to  hookworm   dis- 
ease, 17 
Perversion  of  appetite  in  hookworm 

disease,  146 
Perversions    in    hookworm    disease, 
153 
sexual,  in  hookworm  disease,  153 
Pills,  Blaud's,  in  anemia,  228 
in  treatment,  229 
Dr.    Ford's   iron    and    quinine,   in 
anemia,  227 
Pneumonia    intercurrent    in    hook- 
worm disease,  187 
prevalence  of,  in  southern  states, 
187 
Podophvllin,  dose  of,   in  treatment, 
225 
treatment,  225 
Porto  Rico  commission,  report  of,  43 
commission   for  study  of  anemia 
in,  32 
Post-mortem    appearance    of    hook- 
worm subject,  94 
of  arteries,  95 
of  blood,  100 
of  bone  marrow,  100 
of  brain,  100 
of  heart,  94 

of  hemolymph  glands,  100 
of  intestines.  96,  100 
of  kidneys,  95 
of  liver,  95 
of  lungs,  95 

of  mesenteric  glands,  100 
of  mucosa,  97 
of  pancreas,  95 
of  skin,  94 
of  spleen,  95 
of  stomach,  96 
Pregnancy  contraindicates  adminis- 
tration of  thymol,  218 


Pregnancy — cont'd. 

unfavorable  element  in  prognosis, 
186 
Preparation,     making,     for     micro- 
scopic examination,  158 
wet,  to  be  used  in  microscopic  ex- 
amination, 161 
Prevention    of    infection    by    larvae, 
203 
of   soil    infection    in   prophylaxis, 
192 
Privy,  construction  of  sanitary,  195 
sanitary,  necessary  in  prophylax- 
is, 194 
Privies  source  of  infection,  86 
country      schools      not     provided 

with,  91 
disposition  of  feces  in  absence  of, 
89 
Prognosis,  182 

Charcot-Leyden  crystals  as  guide 

in,  185 
eosinophiles  as  guide  in,  184 
favorable,  in  proportion  to  treat- 
ment, 188 
food  as  a  factor  in,  182 
pregnancy     unfavorable     element 
in.  186 
Progressive     anemia     characteristic 

of  hookworm  disease,   17 
Prophylaxis,  189 

extermination    of   hookworms   in, 

190 
prevention  of  soil  infection  in,  192 
sanitary  privy  necessary  in,  194 
Psychic    effects    in    hookworm    dis- 
ease, 143 
Pulse  in  hookworm  disease,  143 
Purdy  centrifuge,  172 

QuAiS'TiTY  of  feces  passed  varies 
with  conditions,  166 

Rainy  weather,  infection  during,  92 

Range  of  latitude  of  hookworm  dis- 
ease, 33 

Ratio  of  hemorrhages  to  number  of 
hookworms,  99 

Relation  of  moisture  to  hookworm 
infection,  43 

Remedies  for  dirt  eating,  147 

Repetition  of  thymol  treatment,  221 
reason  for,  221 

Report  of  Porto  Rico  Commission, 
43 

Requirements  of  hookworm  eradica- 
tion, 191 

Respiratory  system,  symptoms  of, 
141 


248 


INDEX. 


Results    from    thymol    in    expelling 
hookworms,  220 

Saa'dy  soil  as  a  factor  in  hookworm 

disease,  43 
Sanitary  privy,  construction  of,  195 
privies  necessary  in  prophyjaxis, 
194 
Sardinia,  hookworm  disease  in,  33 
Scientific  Aame  of  hookworm,  17 

origin  of,  for  hookworm,  21 
Schools,  country,  not  provided  with 

privies,  91 
Secondary  type  of  anemia,  136 
Servia,  hookworm  disease  in,  33 
Sexual  glands,  male,  of  hookworm, 
57 
perversions  in  hookworm  disease, 
153 
Shade  as  a  factor  in  hatching  ova, 
74 
in  hookworm  disease,  43 
Shoes,  infection  through  wet,  92 
Sicily,  hookworm  disease  in,   33 
Skin  infection,  69 
by  larvte-containing  water,  45 
dermatitis  produced  by,  76 
only  practical  mode,  93 
Skin,  infection  through,  76 

color    of,    in    chronic    hookworm 

disease,  141 
post-mortem  appearance  of,  94 
Slide,  going  over,  in  microscopic  ex- 
amination,  164 
Slides,    number    of,    in    microscopic 
examination,  161 
size   of,    in   microscopic  examina- 
tion, 159 
Slight  cases   of  hookworm    disease, 

132 
Social  position  as  a  factor  in  hook- 
worm disease,  44 
Soil,    sandy,    as    a    factor    in    hook- 
worm disease,  43 
Solution,  Fowler's,  in  anemia,  228 
Solvents   to   be    avoided    in   thymol 

treatment,  214 
Southern  states,  prevalence  of  pneu- 
monia in,  187 
Spain,  hookworm  disease  in,  33 
Special  methods  for  finding  ova,  171 
Spleen,  post-mortem  appearance  of, 
95 
symptoms  of,  141 
Spread  of  hookworm  disease,  23 

cause  of,  23 
Stool,  number  of  ova  passed  in,  71 
treatment   before    ova    appear    in, 
209 


Stomach,    post-mortem    appearance 

of,  96 
Stricture  of  intestine  in  hookworm 

disease,  188 
Strongylidse,  description  of,  47 
family,  hooltworm  belongs  to,  46 
synonyms  for,  47 
Strongylinte    sub-family,    hookworm 

belongs  to,  46 
Substance    delaying    blood    coagula- 
tion, 105 
Sucking   an    important  function    of 

hookworm,  102 
Sunlight,  effect  of,  on  ova,  65 
Switzerlan(J,   hookworm   disease   in, 

22 
Symptom,    anemia    as    a,    in    hook- 
worm disease,  135 
Symptomatic  diagnosis,  155 
Symptomatology,    115 
Symptoms     in    liookworm    disease. 

See  Symptoms. 
Symptoms,  hookworm  disease,  like 
chlorosis,  26 
hookworm    subject    may    present 

no  recognizable,  116 
of  blood,  135 

of  circulatory  system,  17,  142 
of  digestive  system,  17,  144 
of  dirt  eating,  25 
of  dyspnea,  142 
of  eyes,  151 

of  genito-urinary  system,  150 
of  hookworm  disease,  17 

altered  by  other  diseases,  154 
due  to  loss  of  blood,  115 
due  to  toxin,   115 
of  joints,  137 
of  liver,  141 

of  nervous  system,  17,   151 
of  respiratory  system,  141 
of  skin,  137 
of  spleen,  141 

on  part  of  certain  tissues  and  or- 
gans, 135 
thymol  intoxication,  216 
Synonyms  for  hookworm,  18,  47 
for  strongylidEe,  47 
for  necator  Americanus,  59 
System,    circulatory,    symptoms    of, 
17,  142 
digestive,  symptoms  of,  17,  144 
genito-urinary,   symptoms  of,   150 
nervous,  symptoms  of,   17,  151 
respiratory,  symptoms  of,  141 

Telemann's  method  for  finding  ova, 
171 
solution  necessary  for,  171 


IXDEX. 


1^4^ 


Temperature     most     favorable     for 

larvae,   42 
Test,  blotting  paper,  for  hookworm 

disease,  178 
Thymol,   dose  of,  in  treatment,   212 
first  use  of,  for  hookworm,  212 
for  expulsion  of  feces  for  exami- 
nation, 177 
intoxication  symptoms,  216 

treatment  of,  219 
mode    of     administration    of,    in 

treatment,  213 
pregnancy  contraindicates  admin- 
istration of,  218 
results    from,    in    expelling    hook- 
worms, 220 
treatment,  diet  during,  215 
hookworms  expelled  in,  223 
ova  absent  after,  166 
ova  present  after,  166 
patient   to   remain   in  bed   dur- 
ing, 215 
repetition  of,   221 
solvents  to  be  avoided  in,  214 
time  for  giving,  215 
Time  for  finding  larvae  after  evacu- 
ation, 170 
for  giving  thymol  treatment,   215 
required  in  microscopic  examina- 
tion. 161 
Tissues,   symptoms   on   part  of  cer- 
tain, 135 
Tobacco,    chewing,    as    remedy    for 

dirt  eating,  147 
Toe  itch,  hookworm  in,  79 
Toxin  caused  by  hookworm,  111 
hemolytic,    in   hookworm    disease, 

106 
symptoms    of    hookworm    disease 
due  to,  115 
Treatment,  207 
anthelmintic.  230 
before  ova  appear  in  stool,  209 
beta-naphtol,  222 

hookworms  expelled  in,  223 
Blaud's  pills  in,  229 
blood  charts  in,  229,  231 
diagnosis  by  examination  of  stool 

after,  177 
dose  of  beta-naphtol  in,  222 
of  eucalyptus  in,  224 
of  male  fern  in.  223 
of  podophyllin  in,  225 
of  thymol  in.   212 
eucalyptus,  224 
favorable  prognosis  in  proportion 

to,  188 
gain  in  height  after,  235 
in  weight  after,  235 


Treatment — cont'd, 
general,  of  hookworm  disease,  225 

important  factors  in,  225 
improvement  after,  229 
male  fern,  223 
mode  of  administration  of  thymol 

in,  213 
of  anemia  in   hookworm    disease, 

225 
of  ground  itch,  207 
of  hookworms  in  intestine,  210 
of  thymol  intoxication  symptoms, 

219 
other  drugs  in  hookworm,  225 
other  methods  of  hookworm,  222 
podophyllin,  225 
thymol,   diet   during,   215 
hookworms  expelled  in,   223 
ova  absent  after,  166 
ova  present  after,  166 
patient  to   remain   in   bed   dur- 
ing, 215 
repetition  of,  221 
solvents  to  be  avoided  in,  214 
time  for  giving,  215 
Tropics,  cause  of  greater  hookworm 

infection  in,  75 
Tuberculosis,      hookworm      disease 

mistaken  for,  183 
Type,    mild,    of    hookworm    disease, 
122 
secondary,  of  anemia,  136 
severe,  of  hookworm  disease,  125 
how  recognized,  127 
Types   of  hookworm   disease,   divis- 
ions of,  130 

Ulcers  caused  by  hookworm.  111 
Uncinaria  Americana,  30 
ova  of,  65 
as  name  for  hookworm  in  Amer- 
ica, 49 
duodenalis  as  name  for  hookworm, 
17 
ova  of,  65 
Uncinariasis.      See    Hookworm    dis- 
ease. 
United  States,  dirt  eating  in,  24 

hookworm  disease  in,  24,  37 
Urine  in  hookworm  disease,  150 
Uteri  of  hookworm,  57 

V.JlSeline,  effect  of,  on  larvs,  67 
Vegetable    cells,    differentiation    of 
hookworm  ova  from,  169 

Water,  drinking,  as  a  factor  in  in- 
fection, 75 

effect  of,  on  larvfs,  67,  203 


250 


INDEX. 


Water — cont'd. 

skin    infection    by    larvffi-contain- 
ing,  45 

sore,  hookworm  in,  79 
Weather,  infection  during  rainy,  92 
Weight,  gain  in,  after  treatment,  235 


Wet  shoes,  infection  through,  92 
Worm   infection,    eosinophilia    pres- 
ent in,  180 
Worms,  dirt  eating  cause  of,  147 

ZooLOGic  features  of  hookworm,  46 


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Hookworm  disease • 


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